I can access Apple Wallet on my phone, but I have no icon for it. How do I get the icon to appear as an app ?

Are you sure it's not on the phone?

Have you tried to locate it using the Spotlight Search?

The thing is that you could accidentally put the app in a folder. If so, it will appear in the search results with the name of the folder next to it.

If you can't see the Wallet app in the search results, force restart your iPhone.

If this step didn't help, restore your iPhone.

I have the same problem but on my iPad. I've just answered all the questions to set up OS13 including on Apple Pay and Wallet, detailing 2 credit cards. All validated - but no Wallet icon to access.

And yes, I've tried Spotlight ...