1. Open the WeChat applet "Yangchengtong" and log in the account.

2. On the applet home page or personal center page, find or click "Invoice" or similar options.

3. After entering the "billing" page, fill in the corresponding billing information, including the invoice header, taxpayer identification number, contact phone number, mailing address, etc.

4. Select invoice types as required, such as ordinary invoices and special VAT invoices.

5. Fill in the complete purchase details, including the purchase date and amount.

6. Submit the invoice application and wait for approval.

7. After approval, the system will automatically generate an electronic invoice or mail an entity invoice to you.