Why does the app store require SMS verification every time when purchasing an app using UnionPay payment?

Open the App Store application from the desktop, go to the bottom of the homepage, click your Apple ID account, select, and re-complete the bank card information. For credit cards, re-enter the verification security code, wait for UnionPay to send a verification SMS, fill in and submit The verification is successful.

1. Click Settings on iPhone to enter.

2. Click iTunes Store and App Store to enter.

3. Click Apple ID. If it is not set, set it. If it is, just click it! Select View Apple ID, enter the password and select "OK" to enter account settings and click payment information.

4. After entering, you can set up a bank card, select None.

5. Return to the previous page, click on the country or region, select China after entering, and then a page welcoming you to purchase will appear.