How do I add a bank card to wallet

See here: link-> Set up Apple Pay - Apple Support

If you don't get the option of adding a card by pressing the (+) icon in Wallet. Make sure you are in a region where Apple Pay is supported, and your iPhone is set to said region correctly in Settings->General->Language & Region->Region

Link-> Countries and regions that support Apple Pay - Apple Support

First you must be in a county and region that support Apple Pay.

Countries and regions that support Apple Pay - Apple Support

Then your particular bank must support Apple Pay (not all do).

Apple Pay participating banks in Canada, Latin America, and the United States - Apple Support

If you've made it this far:

How to add Apple Card to your Apple devices - Apple Support