Add customer JSON import

src/pages/rest/modules/import/index.md

@@ -48,6 +48,33 @@ The `import/json` endpoint is designed for JSON data:
 *  Convert your CSV into JSON using any trustworthy online converter.
 *  When converting CSV to JSON using standard tools or libraries, special characters within the data are typically escaped automatically. Ensure that any manual edits or custom conversion processes handle this escaping appropriately.
 
+#### Customer imports in Adobe Commerce as a Cloud Service
+
+In Adobe Commerce as a Cloud Service, the customer import API (POST /V1/import/json with entity: "customer") does not support `assistance_allowed`.
+
+If you need to create or modify customers that have [remote shopping assistance enabled](https://experienceleague.adobe.com/en/docs/commerce-admin/customers/customer-accounts/manage/login-as-customer#customer-account-permission-for-remote-shopping-assistance), you can:
+
+* Use `POST /V1/async/bulk/customers` to bulk create customers with assistance_allowed pre-enabled.
+
+    ```json
+        {
+          "customer": {
+            "email": "user@example.com",
+            "firstname": "User",
+            "lastname": "One",
+            "website_id": 1,
+            "extension_attributes": {"assistance_allowed": 2}
+          },
+          "password": "Password123!"
+        }
+    ```
+
+* Use the `PUT /V1/customers/{id}` endpoint to modify existing customers individually.
+
+    ```json
+    {"customer": {"extension_attributes": {"assistance_allowed": 2}}}
+    ```
+
 ### Validation Strategy
 
 A validation strategy is mandatory. Depending on your chosen strategy, the API will either proceed with the import or abort it upon encountering invalid rows.