How can I add a credit card to my Apple Wallet?

You go to your Apple Wallet App, open it, depress the plus sign and use your iPhone to focus on your credit card number. Then follow the prompts. Your Bank will review and approve your use of that CC on your Apple Wallet App with Apple Pay.

[Edited by Moderator]

There are several possible reasons you might be experiencing issues. So let’s start with a few basic steps. I’ve added links to support articles that may offer solutions to issues you might encounter. 

Are you in a country or region that supports Apple Pay?

Countries and regions that support Apple Pay - Apple Support

Does your financial institution support Apple Pay?

Apple Pay participating banks in Asia/Pacific, Africa, Europe Latin America, Middle East and United States - Apple Support

Confirm your region is set correctly.

Change the language and region on iPhone - Apple Support

Change your Apple ID country or region