add to wallet not working on iPhone 13

You weren’t specific so I assumed you wanted to add a payment card, sorry.

Have you added this parking pass from this particular vendor successfully in the past? It could be an invalid link or a problem on the vendor’s end. I just had an issue adding admission tickets and a parking pass with a vendor because I had to drill down so deep on the website before I could find the option to do so.

Maybe something in here here will help.

Add, use, and share boarding passes, tickets, and other passes in Apple Wallet - Apple Support

If nothing in there helps, post back with more details.

Start with the steps in here.

If you can't add a card to Apple Wallet to use with Apple Pay - Apple Support