Hello saurav106,
Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with adding a card to your wallet. Try the steps listed here to see if they resolve the issue: If you can't add a card to Apple Wallet to use with Apple Pay - Apple Support
"Learn what steps to take if you can't add a card to the Wallet app to use with Apple Pay.
- Check that you're able to use Apple Pay:
- Check for services outages or connection issues.
- If you see the message "Could Not Add Card" or "Invalid Card," contact your bank or card issuer.
Apple does not approve or decline cards for use with Apple Pay. If your card was declined, contact your bank or card issuer.
If you need help adding a card, learn how to set up Apple Pay."
We hope this helps.
Cheers!