Thanks for reaching out RahulBangaru,
It sounds like you're having some trouble adding cards to Wallet. We can help.
Without knowing the reason you aren't able to add cards to your Wallet, we recommend following these steps to Set up Apple Pay in Wallet on iPhone first.
If you find the behavior still continues, let us know some specifics of what you are running into, and we can give more targeted advice.
Hope that helps.
Take care.