How to change credit card on file

This is most likely what you are trying to accomplish. But there could be several cards on file. Please review the support article linked below for other devices etc.

>> Update your payment method on your iPhone or iPad

1. Open the Settings app.
2. Tap your name.
3. Tap Payment & Shipping. You might be asked to sign in with your Apple ID.
4. Tap Add Payment Method, enter the new payment method, then tap Done.
5. Tap Edit.
6. Tap the red delete button next to the old payment method, then tap Delete. <<

If you need to change or update your Apple ID payment method - Apple Support