diff --git a/docs/order.sh b/docs/order.sh
index 8f34e83..aa2ec69 100644
--- a/docs/order.sh
+++ b/docs/order.sh
@@ -115,4 +115,25 @@ curl --location 'https://land.dbiz.com//api/method/building_material.building_ma
             "account_name": "NGUYEN MINH CHAU"
         }
     }
-}
\ No newline at end of file
+}
+
+#upload bill
+curl --location 'https://land.dbiz.com//api/method/upload_file' \
+--header 'Cookie: sid=a0cbe3ea6f9a7e9cf083bbe3139eada68d2357eac0167bcc66cda17d; sid=a0cbe3ea6f9a7e9cf083bbe3139eada68d2357eac0167bcc66cda17d' \
+--header 'X-Frappe-Csrf-Token: 6ff3be4d1f887dbebf86ba4502b05d94b30c0b0569de49b74a7171a9' \
+--form 'file=@"/C:/Users/tiennld/Downloads/logo_crm.png"' \
+--form 'is_private="1"' \
+--form 'folder="Home/Attachments"' \
+--form 'doctype="Sales Order"' \
+--form 'docname="SAL-ORD-2025-00058-1"' \
+--form 'optimize="true"'
+
+
+#order detail
+curl --location 'https://land.dbiz.com//api/method/building_material.building_material.api.sales_order.get_detail' \
+--header 'Cookie: sid=a0cbe3ea6f9a7e9cf083bbe3139eada68d2357eac0167bcc66cda17d; sid=a0cbe3ea6f9a7e9cf083bbe3139eada68d2357eac0167bcc66cda17d' \
+--header 'X-Frappe-Csrf-Token: 6ff3be4d1f887dbebf86ba4502b05d94b30c0b0569de49b74a7171a9' \
+--header 'Content-Type: application/json' \
+--data '{
+    "name" : "SAL-ORD-2025-00058-1"
+}'
\ No newline at end of file
diff --git a/html/payment-qr.html b/html/payment-qr.html
index 508bef6..90597d0 100644
--- a/html/payment-qr.html
+++ b/html/payment-qr.html
@@ -12,9 +12,11 @@
     <div class="page-wrapper">
         <!-- Header -->
         <div class="header">
-            <a href="checkout.html" class="back-button">
+            <!--<a href="checkout.html" class="back-button">
                 <i class="fas fa-arrow-left"></i>
-            </a>
+            </a>-->
+            <div style="width: 32px;"></div>
+
             <h1 class="header-title">Thanh toán</h1>
             <button class="back-button" onclick="openInfoModal()">
                 <i class="fas fa-info-circle"></i>
diff --git a/lib/core/constants/api_constants.dart b/lib/core/constants/api_constants.dart
index a93f447..9f51028 100644
--- a/lib/core/constants/api_constants.dart
+++ b/lib/core/constants/api_constants.dart
@@ -227,6 +227,12 @@ class ApiConstants {
   /// Returns: { "message": { "qr_code": "...", "amount": null, "transaction_id": "...", "bank_info": {...} } }
   static const String generateQrCode = '/building_material.building_material.api.v1.qrcode.generate';
 
+  /// Upload file (bill/invoice/attachment) (requires sid and csrf_token)
+  /// POST /api/method/upload_file
+  /// Form-data: { "file": File, "is_private": "1", "folder": "Home/Attachments", "doctype": "Sales Order", "docname": "SAL-ORD-2025-00058-1", "optimize": "true" }
+  /// Returns: { "message": { "file_url": "...", "file_name": "...", ... } }
+  static const String uploadFile = '/upload_file';
+
   /// Get user's orders
   /// GET /orders?status={status}&page={page}&limit={limit}
   static const String getOrders = '/orders';
diff --git a/lib/features/cart/presentation/pages/checkout_page.dart b/lib/features/cart/presentation/pages/checkout_page.dart
index 1ec1954..64e8cf7 100644
--- a/lib/features/cart/presentation/pages/checkout_page.dart
+++ b/lib/features/cart/presentation/pages/checkout_page.dart
@@ -59,6 +59,8 @@ class CheckoutPage extends HookConsumerWidget {
     // Price negotiation
     final needsNegotiation = useState<bool>(false);
 
+    final needsContract = useState(false);
+
     // Watch API provider for payment terms
     final paymentTermsListAsync = ref.watch(paymentTermsListProvider);
 
@@ -240,6 +242,40 @@ class CheckoutPage extends HookConsumerWidget {
               // Price Negotiation Section
               PriceNegotiationSection(needsNegotiation: needsNegotiation),
 
+              const SizedBox(height: AppSpacing.md),
+
+
+              Container(
+                margin: const EdgeInsets.symmetric(horizontal: AppSpacing.md),
+                padding: const EdgeInsets.symmetric(horizontal: AppSpacing.md),
+                decoration: BoxDecoration(
+                  color: const Color(0xFFFFF8E1),
+                  borderRadius: BorderRadius.circular(AppRadius.card),
+                  border: Border.all(color: const Color(0xFFFFD54F)),
+                ),
+                child: Row(
+                  children: [
+                    Checkbox(
+                      value: needsContract.value,
+                      onChanged: (value) {
+                        needsContract.value = value ?? false;
+                      },
+                      activeColor: AppColors.warning,
+                    ),
+                    const Expanded(
+                      child: Text(
+                        'Yêu cầu hợp đồng',
+                        style: TextStyle(
+                          fontSize: 15,
+                          fontWeight: FontWeight.w600,
+                          color: Color(0xFF212121),
+                        ),
+                      ),
+                    ),
+                  ],
+                ),
+              ),
+
 
               const SizedBox(height: AppSpacing.md),
 
diff --git a/lib/features/orders/data/datasources/order_remote_datasource.dart b/lib/features/orders/data/datasources/order_remote_datasource.dart
index 0c0c421..b65a0ac 100644
--- a/lib/features/orders/data/datasources/order_remote_datasource.dart
+++ b/lib/features/orders/data/datasources/order_remote_datasource.dart
@@ -3,6 +3,7 @@
 /// Handles API calls for order-related data.
 library;
 
+import 'package:dio/dio.dart';
 import 'package:worker/core/constants/api_constants.dart';
 import 'package:worker/core/network/dio_client.dart';
 import 'package:worker/features/orders/data/models/order_status_model.dart';
@@ -194,4 +195,56 @@ class OrderRemoteDataSource {
       throw Exception('Failed to generate QR code: $e');
     }
   }
+
+  /// Upload bill/invoice file
+  ///
+  /// Calls: POST /api/method/upload_file
+  /// Form-data: {
+  ///   "file": File,
+  ///   "is_private": "1",
+  ///   "folder": "Home/Attachments",
+  ///   "doctype": "Sales Order",
+  ///   "docname": "SAL-ORD-2025-00058-1",
+  ///   "optimize": "true"
+  /// }
+  /// Returns: { "message": { "file_url": "...", "file_name": "...", ... } }
+  Future<Map<String, dynamic>> uploadBill({
+    required String filePath,
+    required String orderId,
+  }) async {
+    try {
+      // Create multipart form data
+      final formData = FormData.fromMap({
+        'file': await MultipartFile.fromFile(
+          filePath,
+          filename: filePath.split('/').last,
+        ),
+        'is_private': '1',
+        'folder': 'Home/Attachments',
+        'doctype': 'Sales Order',
+        'docname': orderId,
+        'optimize': 'true',
+      });
+
+      final response = await _dioClient.post<Map<String, dynamic>>(
+        '${ApiConstants.frappeApiMethod}${ApiConstants.uploadFile}',
+        data: formData,
+      );
+
+      final data = response.data;
+      if (data == null) {
+        throw Exception('No data received from uploadBill API');
+      }
+
+      // Extract file info from Frappe response
+      final message = data['message'] as Map<String, dynamic>?;
+      if (message == null) {
+        throw Exception('No message field in uploadBill response');
+      }
+
+      return message;
+    } catch (e) {
+      throw Exception('Failed to upload bill: $e');
+    }
+  }
 }
diff --git a/lib/features/orders/data/repositories/order_repository_impl.dart b/lib/features/orders/data/repositories/order_repository_impl.dart
index 6bd61dc..ce176d0 100644
--- a/lib/features/orders/data/repositories/order_repository_impl.dart
+++ b/lib/features/orders/data/repositories/order_repository_impl.dart
@@ -65,4 +65,19 @@ class OrderRepositoryImpl implements OrderRepository {
       throw Exception('Failed to generate QR code: $e');
     }
   }
+
+  @override
+  Future<Map<String, dynamic>> uploadBill({
+    required String filePath,
+    required String orderId,
+  }) async {
+    try {
+      return await _remoteDataSource.uploadBill(
+        filePath: filePath,
+        orderId: orderId,
+      );
+    } catch (e) {
+      throw Exception('Failed to upload bill: $e');
+    }
+  }
 }
diff --git a/lib/features/orders/domain/repositories/order_repository.dart b/lib/features/orders/domain/repositories/order_repository.dart
index a5ca754..425100a 100644
--- a/lib/features/orders/domain/repositories/order_repository.dart
+++ b/lib/features/orders/domain/repositories/order_repository.dart
@@ -26,4 +26,10 @@ abstract class OrderRepository {
 
   /// Generate QR code for payment
   Future<Map<String, dynamic>> generateQrCode(String orderId);
+
+  /// Upload bill/invoice file
+  Future<Map<String, dynamic>> uploadBill({
+    required String filePath,
+    required String orderId,
+  });
 }
diff --git a/lib/features/orders/presentation/pages/payment_qr_page.dart b/lib/features/orders/presentation/pages/payment_qr_page.dart
index 2b73518..2c3b168 100644
--- a/lib/features/orders/presentation/pages/payment_qr_page.dart
+++ b/lib/features/orders/presentation/pages/payment_qr_page.dart
@@ -11,15 +11,18 @@
 library;
 
 import 'dart:async';
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import 'package:go_router/go_router.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:image_picker/image_picker.dart';
 import 'package:qr_flutter/qr_flutter.dart';
 
 import 'package:worker/core/constants/ui_constants.dart';
+import 'package:worker/core/router/app_router.dart';
 import 'package:worker/core/theme/colors.dart';
 import 'package:worker/features/orders/presentation/providers/order_repository_provider.dart';
 
@@ -47,6 +50,10 @@ class PaymentQrPage extends HookConsumerWidget {
     final remainingSeconds = useState<int>(900);
     final timer = useRef<Timer?>(null);
 
+    // Upload state
+    final isUploadingBill = useState<bool>(false);
+    final selectedImagePath = useState<String?>(null);
+
     // Fetch QR code data
     useEffect(() {
       Future<void> fetchQrCode() async {
@@ -146,8 +153,27 @@ class PaymentQrPage extends HookConsumerWidget {
 
             const SizedBox(height: AppSpacing.md),
 
+            // Image Preview Section
+            _buildImagePreviewSection(
+              context,
+              selectedImagePath.value,
+              () async {
+                await _selectImage(context, selectedImagePath);
+              },
+            ),
+
+            const SizedBox(height: AppSpacing.md),
+
             // Action Buttons
-            _buildActionButtons(context),
+            _buildActionButtons(
+              context,
+              ref,
+              isUploadingBill.value,
+              selectedImagePath.value != null,
+              () async {
+                await _uploadBill(context, ref, selectedImagePath, isUploadingBill);
+              },
+            ),
 
             const SizedBox(height: AppSpacing.md),
 
@@ -452,44 +478,174 @@ class PaymentQrPage extends HookConsumerWidget {
     );
   }
 
-  /// Build action buttons
-  Widget _buildActionButtons(BuildContext context) {
-    return Padding(
-      padding: const EdgeInsets.symmetric(horizontal: AppSpacing.md),
-      child: Row(
+  /// Build image preview section
+  Widget _buildImagePreviewSection(
+    BuildContext context,
+    String? imagePath,
+    VoidCallback onSelectImage,
+  ) {
+    return Container(
+      margin: const EdgeInsets.symmetric(horizontal: AppSpacing.md),
+      padding: const EdgeInsets.all(AppSpacing.md),
+      decoration: BoxDecoration(
+        color: Colors.white,
+        borderRadius: BorderRadius.circular(AppRadius.card),
+        boxShadow: [
+          BoxShadow(
+            color: Colors.black.withValues(alpha: 0.05),
+            blurRadius: 8,
+            offset: const Offset(0, 2),
+          ),
+        ],
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
         children: [
-          // Confirmed Payment Button
-          Expanded(
-            child: OutlinedButton.icon(
-              onPressed: () => _confirmPayment(context),
-              icon: const FaIcon(FontAwesomeIcons.check, size: 18),
-              label: const Text(
-                'Đã thanh toán',
-                style: TextStyle(fontSize: 15, fontWeight: FontWeight.w600),
-              ),
-              style: OutlinedButton.styleFrom(
-                foregroundColor: AppColors.primaryBlue,
-                side: const BorderSide(
-                  color: AppColors.primaryBlue,
-                  width: 1.5,
-                ),
-                padding: const EdgeInsets.symmetric(vertical: 14),
-                shape: RoundedRectangleBorder(
-                  borderRadius: BorderRadius.circular(AppRadius.button),
-                ),
-              ),
+          const Text(
+            'Ảnh hóa đơn',
+            style: TextStyle(
+              fontSize: 16,
+              fontWeight: FontWeight.bold,
+              color: Color(0xFF212121),
             ),
           ),
-          const SizedBox(width: AppSpacing.sm),
+          const SizedBox(height: AppSpacing.md),
 
-          // Upload Proof Button
-          Expanded(
+          // Image preview or placeholder
+          InkWell(
+            onTap: onSelectImage,
+            borderRadius: BorderRadius.circular(AppRadius.card),
+            child: Container(
+              width: double.infinity,
+              height: 200,
+              decoration: BoxDecoration(
+                color: const Color(0xFFF4F6F8),
+                borderRadius: BorderRadius.circular(AppRadius.card),
+                border: Border.all(
+                  color: const Color(0xFFE2E8F0),
+                  width: 2,
+                  style: BorderStyle.solid,
+                ),
+              ),
+              child: imagePath != null
+                  ? ClipRRect(
+                      borderRadius: BorderRadius.circular(AppRadius.card - 2),
+                      child: Stack(
+                        children: [
+                          Image.file(
+                            File(imagePath),
+                            width: double.infinity,
+                            height: double.infinity,
+                            fit: BoxFit.cover,
+                          ),
+                          Positioned(
+                            top: 8,
+                            right: 8,
+                            child: Container(
+                              decoration: BoxDecoration(
+                                color: Colors.black.withValues(alpha: 0.6),
+                                borderRadius: BorderRadius.circular(20),
+                              ),
+                              padding: const EdgeInsets.symmetric(
+                                horizontal: 12,
+                                vertical: 6,
+                              ),
+                              child: Row(
+                                mainAxisSize: MainAxisSize.min,
+                                children: const [
+                                  FaIcon(
+                                    FontAwesomeIcons.pen,
+                                    color: Colors.white,
+                                    size: 12,
+                                  ),
+                                  SizedBox(width: 6),
+                                  Text(
+                                    'Đổi ảnh',
+                                    style: TextStyle(
+                                      color: Colors.white,
+                                      fontSize: 12,
+                                      fontWeight: FontWeight.w500,
+                                    ),
+                                  ),
+                                ],
+                              ),
+                            ),
+                          ),
+                        ],
+                      ),
+                    )
+                  : Column(
+                      mainAxisAlignment: MainAxisAlignment.center,
+                      children: [
+                        Container(
+                          width: 60,
+                          height: 60,
+                          decoration: BoxDecoration(
+                            color: AppColors.primaryBlue.withValues(alpha: 0.1),
+                            borderRadius: BorderRadius.circular(30),
+                          ),
+                          child: const Icon(
+                            FontAwesomeIcons.image,
+                            color: AppColors.primaryBlue,
+                            size: 24,
+                          ),
+                        ),
+                        const SizedBox(height: 12),
+                        const Text(
+                          'Chạm để chọn ảnh hóa đơn',
+                          style: TextStyle(
+                            fontSize: 14,
+                            color: AppColors.grey500,
+                            fontWeight: FontWeight.w500,
+                          ),
+                        ),
+                        const SizedBox(height: 4),
+                        const Text(
+                          'Hỗ trợ: JPG, PNG',
+                          style: TextStyle(
+                            fontSize: 12,
+                            color: AppColors.grey500,
+                          ),
+                        ),
+                      ],
+                    ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  /// Build action buttons
+  Widget _buildActionButtons(
+    BuildContext context,
+    WidgetRef ref,
+    bool isUploading,
+    bool hasImage,
+    VoidCallback onUpload,
+  ) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: AppSpacing.md),
+      child: Column(
+        children: [
+          // Upload Bill Button
+          SizedBox(
+            width: double.infinity,
             child: ElevatedButton.icon(
-              onPressed: () => _uploadProof(context),
-              icon: const FaIcon(FontAwesomeIcons.camera, size: 18),
-              label: const Text(
-                'Upload bill',
-                style: TextStyle(fontSize: 15, fontWeight: FontWeight.w600),
+              onPressed: (isUploading || !hasImage) ? null : onUpload,
+              icon: isUploading
+                  ? const SizedBox(
+                      width: 18,
+                      height: 18,
+                      child: CircularProgressIndicator(
+                        strokeWidth: 2,
+                        valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
+                      ),
+                    )
+                  : const FaIcon(FontAwesomeIcons.camera, size: 18),
+              label: Text(
+                isUploading ? 'Đang upload...' : 'Upload bill chuyển khoản',
+                style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600),
               ),
               style: ElevatedButton.styleFrom(
                 backgroundColor: AppColors.primaryBlue,
@@ -499,6 +655,33 @@ class PaymentQrPage extends HookConsumerWidget {
                 shape: RoundedRectangleBorder(
                   borderRadius: BorderRadius.circular(AppRadius.button),
                 ),
+                disabledBackgroundColor: AppColors.grey100,
+                disabledForegroundColor: AppColors.grey500,
+              ),
+            ),
+          ),
+          const SizedBox(height: AppSpacing.sm),
+
+          // Back to Home Button
+          SizedBox(
+            width: double.infinity,
+            child: OutlinedButton.icon(
+              onPressed: isUploading ? null : () => context.goNamed(RouteNames.home),
+              icon: const FaIcon(FontAwesomeIcons.house, size: 18),
+              label: const Text(
+                'Quay về trang chủ',
+                style: TextStyle(fontSize: 15, fontWeight: FontWeight.w600),
+              ),
+              style: OutlinedButton.styleFrom(
+                foregroundColor: AppColors.grey900,
+                side: const BorderSide(
+                  color: AppColors.grey100,
+                  width: 1.5,
+                ),
+                padding: const EdgeInsets.symmetric(vertical: 14),
+                shape: RoundedRectangleBorder(
+                  borderRadius: BorderRadius.circular(AppRadius.button),
+                ),
               ),
             ),
           ),
@@ -598,57 +781,209 @@ class PaymentQrPage extends HookConsumerWidget {
     );
   }
 
-  /// Confirm payment
-  void _confirmPayment(BuildContext context) {
-    showDialog<void>(
+  /// Select image for bill
+  Future<void> _selectImage(
+    BuildContext context,
+    ValueNotifier<String?> selectedImagePath,
+  ) async {
+    // Show bottom sheet to select camera or gallery
+    final ImageSource? source = await showModalBottomSheet<ImageSource>(
+      context: context,
+      shape: const RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(AppRadius.card)),
+      ),
+      builder: (context) => Container(
+        padding: const EdgeInsets.all(AppSpacing.md),
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            const Text(
+              'Chọn ảnh hóa đơn',
+              style: TextStyle(
+                fontSize: 18,
+                fontWeight: FontWeight.bold,
+                color: Color(0xFF212121),
+              ),
+            ),
+            const SizedBox(height: AppSpacing.md),
+            ListTile(
+              leading: const FaIcon(
+                FontAwesomeIcons.camera,
+                color: AppColors.primaryBlue,
+              ),
+              title: const Text('Chụp ảnh'),
+              onTap: () => Navigator.of(context).pop(ImageSource.camera),
+            ),
+            ListTile(
+              leading: const FaIcon(
+                FontAwesomeIcons.image,
+                color: AppColors.primaryBlue,
+              ),
+              title: const Text('Chọn từ thư viện'),
+              onTap: () => Navigator.of(context).pop(ImageSource.gallery),
+            ),
+            const SizedBox(height: AppSpacing.sm),
+            TextButton(
+              onPressed: () => Navigator.of(context).pop(),
+              child: const Text('Hủy'),
+            ),
+          ],
+        ),
+      ),
+    );
+
+    if (source == null || !context.mounted) return;
+
+    try {
+      // Pick image
+      final picker = ImagePicker();
+      final pickedFile = await picker.pickImage(
+        source: source,
+        maxWidth: 1920,
+        maxHeight: 1080,
+        imageQuality: 85,
+      );
+
+      if (pickedFile == null || !context.mounted) return;
+
+      selectedImagePath.value = pickedFile.path;
+
+      // Show success feedback
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(
+          content: Row(
+            children: [
+              FaIcon(FontAwesomeIcons.circleCheck, color: Colors.white, size: 20),
+              SizedBox(width: 12),
+              Text('Đã chọn ảnh. Nhấn "Upload bill chuyển khoản" để gửi.'),
+            ],
+          ),
+          backgroundColor: AppColors.success,
+          duration: Duration(seconds: 2),
+        ),
+      );
+    } catch (e) {
+      if (!context.mounted) return;
+
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text('Lỗi khi chọn ảnh: ${e.toString()}'),
+          backgroundColor: AppColors.danger,
+          duration: const Duration(seconds: 2),
+        ),
+      );
+    }
+  }
+
+  /// Upload bill to server
+  Future<void> _uploadBill(
+    BuildContext context,
+    WidgetRef ref,
+    ValueNotifier<String?> selectedImagePath,
+    ValueNotifier<bool> isUploadingBill,
+  ) async {
+    if (selectedImagePath.value == null) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(
+          content: Text('Vui lòng chọn ảnh hóa đơn trước'),
+          backgroundColor: AppColors.danger,
+          duration: Duration(seconds: 2),
+        ),
+      );
+      return;
+    }
+
+    // Show confirmation dialog
+    final bool? confirmed = await showDialog<bool>(
       context: context,
       builder: (context) => AlertDialog(
-        title: const Text('Xác nhận thanh toán'),
+        title: const Text('Xác nhận upload'),
         content: const Text(
-          'Bạn đã hoàn tất thanh toán cho đơn hàng này?',
+          'Bạn có muốn upload hóa đơn này không?',
           style: TextStyle(fontSize: 14),
         ),
         actions: [
           TextButton(
-            onPressed: () => Navigator.of(context).pop(),
-            child: const Text('Chưa'),
+            onPressed: () => Navigator.of(context).pop(false),
+            child: const Text('Hủy'),
           ),
           ElevatedButton(
-            onPressed: () {
-              Navigator.of(context).pop();
-              ScaffoldMessenger.of(context).showSnackBar(
-                const SnackBar(
-                  content: Text('Đã xác nhận thanh toán!'),
-                  backgroundColor: AppColors.success,
-                  duration: Duration(seconds: 2),
-                ),
-              );
-              // Navigate back after delay
-              Future.delayed(const Duration(milliseconds: 500), () {
-                if (context.mounted) {
-                  context.pop();
-                }
-              });
-            },
+            onPressed: () => Navigator.of(context).pop(true),
             style: ElevatedButton.styleFrom(
               backgroundColor: AppColors.primaryBlue,
             ),
-            child: const Text('Đã thanh toán'),
+            child: const Text('Upload'),
           ),
         ],
       ),
     );
-  }
 
-  /// Upload payment proof
-  void _uploadProof(BuildContext context) {
-    // TODO: Implement image picker and upload
-    ScaffoldMessenger.of(context).showSnackBar(
-      const SnackBar(
-        content: Text('Tính năng upload bill đang được phát triển'),
-        duration: Duration(seconds: 2),
-      ),
-    );
+    if (confirmed != true || !context.mounted) return;
+
+    try {
+      // Start upload
+      isUploadingBill.value = true;
+
+      final repository = await ref.read(orderRepositoryProvider.future);
+      final result = await repository.uploadBill(
+        filePath: selectedImagePath.value!,
+        orderId: orderId,
+      );
+
+      if (!context.mounted) return;
+
+      isUploadingBill.value = false;
+
+      // Show success message and navigate
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(
+          content: Row(
+            children: [
+              FaIcon(FontAwesomeIcons.circleCheck, color: Colors.white, size: 20),
+              SizedBox(width: 12),
+              Text('Upload hóa đơn thành công!'),
+            ],
+          ),
+          backgroundColor: AppColors.success,
+          duration: Duration(seconds: 2),
+        ),
+      );
+
+      // Navigate to order success page after successful upload
+      Future.delayed(const Duration(milliseconds: 500), () {
+        if (context.mounted) {
+          context.pushReplacementNamed(
+            RouteNames.orderSuccess,
+            queryParameters: {
+              'orderNumber': orderId,
+              'total': amount.toString(),
+              'isNegotiation': 'false',
+            },
+          );
+        }
+      });
+    } catch (e) {
+      if (!context.mounted) return;
+
+      isUploadingBill.value = false;
+
+      // Show error message
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Row(
+            children: [
+              const FaIcon(FontAwesomeIcons.circleXmark, color: Colors.white, size: 20),
+              const SizedBox(width: 12),
+              Expanded(
+                child: Text('Lỗi upload: ${e.toString()}'),
+              ),
+            ],
+          ),
+          backgroundColor: AppColors.danger,
+          duration: const Duration(seconds: 3),
+        ),
+      );
+    }
   }
 
   /// Format currency