Apple wallet icon is missing.

The Apple Wallet app is not available on any of the iPad models. It's a bit misleading on the iPad since you setup Apple Pay under:

Settings/Wallet & Apple Pay

However, the Wallet app itself is not available on the iPad.

You can still use Apple Pay but it's only available for in-app (selected apps) use.

See: Set up and use Apple Pay on your iPhone or iPad - Apple Support

Agreed - not only is it misleading, I just went through 1 apple tech and a senior advisor who wanted to start deleting and reinstalling software and o.s. Because I called asking why the wallet was not showing even though I added a card. After I told the senior tech., I didn't have time and was going to forget it. She called back to offer more assistance after doing some additional research and found that the icon should be there. I thought the iPad too was a mirror of the phone. The card set up ought to say also, using camera , position your card in the frame. I'm kinda a literal person and I happen to use an apple cover which covers the rear camera, so I was placing the card on the screen------ Thought is was some new technology. Well, that didn't work.......