How to add new debit/credit card in Apple Wallet on iPhone

when I go into apple wallet and add a debit/credit card it only has one option that says “previous cards” and I tried multiple times adding a card it still doesn’t work. The only other device I had was a iPad and i don’t really think iPad has apple wallet on there so I’m actually so frustrated on this problem. Any help please?

[Re-Titled by Moderator]