You may need to have a payment method on file, even if the app you want to download is free.
To verify your payment information: Sign in to your Apple ID account page and edit / update your Apple ID details.
https://appleid.apple.com
On the Sidebar click Payment methods -> then tap Payments Methods and tap Manage payment method.
Or -> Change, add or remove Apple ID payment methods
Change, add or remove Apple ID payment methods – Apple Support (UK)
-> Add first the new card, then remove the old one.
See -> Payment methods you can use with your Apple ID
Payment methods you can use with your Apple ID – Apple Support (UK)
You can also use your Apple ID balance as payment method: Add money to your Apple ID balance
Add money to your Apple ID balance – Apple Support (UK)
When you update your payment method -> It would take about 1 to 3 business days in order to process.
when i add my card to apple wallet it says fail and i still cant download
Apple Pay is the way to pay. It replaces your physical cards and cash with a method of payment that is private, easier and safer. Whether you pay in a store, on a website or in an app. This is the new payment.
it is actually the same as paying contactless with your bank card, only via the iPhone.
See -> Use Apple Pay for contactless payments on iPhone
Use Apple Pay for contactless payments on iPhone – Apple Support (UK)