Open the Google Pay app
If you have multiple accounts in Google Pay, select the account you want to update:
In the Google Pay app, at the top right, tap your profile picture or initials
Tap the account you want to use to add a debit or credit card.
Swipe up from the bottom and tap 'Add a card' -> 'Debit or credit card'
Use your camera to capture your card information or enter it manually
You may see a small charge in your Google Pay account after you add your card. This charge verifies that your card and account are valid. The charge will disappear and will not affect your balance.