I am unable to add my credit card in my apple wallet please help to resolve the issue

Why? What happens when you try?

Tap on the (+) icon at the top right of the screen and follow the onscreen prompts.

If you get the Learn More dialog box that takes you to the support document you posted from, make sure your iPhone is set to a country where Apple Pay is supported in Settings ➜ General ➜ Language & Region ➜ Region. click here ➡️ Countries and regions that support Apple Pay - Apple Support

Hello Vikramjot1999, Have you tried following the steps in this Apple Support page? Also not all bank cards are supported in Apple Pay.

Set up Apple Pay in Wallet on iPhone - Apple Support