Can’t but app
I can’t use the money in my Apple ID to buy a game I have no other payment methods on file and it still says unable to purchase
iPhone 12 Pro, iOS 14
Question marked as
If you are buying something that isn't completely free you will need a payment method even if you intend to pay for the item entirely with your Apple Account balance.
This document explains how to 'Change, add, [review,] or remove Apple ID payment methods' on an Apple mobile device, a Mac, or a PC; click here --> https://support.apple.com/HT201266
Additional resources:
'Payment methods that you can use with your Apple ID' --> https://support.apple.com/HT202631