How do I delete my credit card

It isn’t in your phone, it is behind a security wall in your Apple account You only access it through a device such as your phone.

By the way you didn’t make it totally clear. If you just mean the one in your Wallet app tap on it and hit the three dots top right ... and tap ‘remove this card’.

If that doesn’t work just disable your phone passcode and sign out of your icloud account and it will clear wallet.

Only by adding another payment method first .

The card is associated with your Apple account not your phone.