You may need to have a valid payment method on file, even if the app you want to download is free.
You can have a credit card / debit card on file and an Apple Account balance.
If you have set your Apple Account balance as your default payment method, your default payment method will be used first by Apple when you need to make a payment.
Some purchases might require you to have a credit card on file, even if you use your Apple Account balance to make the purchase.
Free apps has also In-app pruchase.
See -> If you can’t download or update apps on your iPhone or iPad
If you can’t download or update apps on your iPhone or iPad – Apple Support (UK)
scroll to point 2 ⤵️
Add a payment method
You may need to have a valid payment method on file, even if the app you want to download is free.
Add a payment method
See also the following Apple articles:
Add a payment method to your Apple ID
Add a payment method to your Apple ID – Apple Support (UK)
- If you want to change your card, you need to add first the new card, then remove the old card.
- or if you want to use your Apple Account balance, you need to set your Apple Account balance as your default payment.
Payment methods you can use with your Apple ID
Payment methods you can use with your Apple ID – Apple Support (UK)
fyi: Not all credit & debit cards seem to work with App Store / iTunes Store, try a different one, or preferably a credit card. If your card is not accepted as a paymenf method, you need to contact your bank.
If you have followed all the steps and instructions and if you still need help, get support from Apple directly -> Get Support or call Apple in your region see -> Contact Apple for support and service or check -> here for more support and assistance.