If you use AliExpress for offline delivery, you must fill in the delivery information and upload the courier number in the AliExpress backend. The specific steps are as follows:

1. Log in to your AliExpress account, find the order to be shipped on the "My Orders" page, and click the "Shipping Review" button.

2. In the pop-up window, select the "Offline Delivery" option and fill in the delivery method, delivery time, courier company and other information.

3. In the "Delivery Order Number" column, fill in the courier number. If you are sending multiple couriers, you can add more delivery information below.

4. After filling in, click the "Save" button. The system will automatically send the filled-in delivery information to the buyer and update the order status to "Shipped".

Please note that if the order number you fill in is incorrect or the logistics information cannot be found, the buyer may file a complaint, causing unnecessary trouble. Therefore, before filling in the order number, be sure to confirm the accuracy of all information.