Follow these steps to add your card to Google Pay:
Open the "Google Wallet" app.
At the bottom of the screen, tap the "Add to Wallet" button.
Select "Payment card." You will see all the cards saved in your Google account.
Choose "New credit or debit card."
To add the card, use the camera or tap the "Enter details manually" button.
At the bottom, tap "Save and continue."
Read the issuer's terms and tap "Accept."
If prompted to verify your card, choose between mobile and email verification depending on what's more convenient for you.
What to do if you receive an error:
In some cases, you may receive an error saying that your card was not added to your Google Pay wallet. Google Pay may decline your card because of your Google account's risk score.
The account score is given by Google Pay based on things like the age of your Google account, current fraud suspension, etc. We have no control over your Google account's score.
We advise you to switch to a different Google account that you own and retry adding the card to Google Pay.