Won’t let me add

If “cards” means credit or debit cards:

Set up Apple Pay - Apple Support

What have you tried to do? The screenshot you provided is not what I see when I launch the wallet app on my iPhone. If you launch the wallet app at the top you should see a + symbol is a black circle. Click on that to add a credit/debit card. Also the first time I added a credit or debit card I needed to also contact the bank the card was with to verify who I was.

Hope this helps.

Paul