How to Update iTunes billing information?
Your Apple ID contains info such as your address, credit card number, country, and email address. If you move, change credit cards, or create a change that affects this info, update your Apple ID therefor that it continues to work correctly. How to
iTunes-billed subscribers can update their payment information on iTunes using a computer or an iOS device.
iOS device.
Computer:
Open iTunes
At the top of the computer screen or iTunes window, select Account > View My Account (and sign in)
Select Manage Payments next to Payment Information
Make the necessary edits to your payment method
Click Done to save the changes
Open the Settings app
Select your name > iTunes & App Stores
Tap your Apple ID > View Apple ID (and sign in, if prompted)
Tap Manage Payments
Add or update your payment method
