How do you replace a credit card?

See -> 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.

See also -> If you need to change or update your Apple ID payment method

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

My actually card has been damaged how do I get a replacement

Contact your bank and ask a new one.