You can use customer scan by following these steps:
Step 1: From the main menu, select "SALE" at the bottom.
Step 2: Enter the sale amount and click scan.
Step 3: Scan options have WeChat Pay, AliPay, Union Pay, PayNow
Step 4: Select Alipay and it generate QR with amount.
Step 5: Now customer scan the QR and make the payment.