Q: how do i delete stored bank cards

Howdy chappers56,

I understand that you're looking to change the billing information used for the Mac App Store, iTunes Store, and App Store on your iPhone. The article linked below details how to go about doing this on any of your devices. This process only needs to be performed once per device per Apple ID. If you use the same Apple ID on all of your devices, then you only need to change it on one device, as your billing information is specific to your Apple ID rather than the device.

Change or remove your Apple ID payment information
https://support.apple.com/en-us/HT201266

Cheers!