Open the Settings app on your phone
Tap Accounts or Passwords & accounts
Select Google or Gmail
Tap the Gmail account you want to remove
Tap Remove account
Confirm by tapping Remove account again
If prompted, enter your phone PIN, pattern, or password
On iPhone, go to Settings
Tap Mail or Passwords & Accounts
Tap the Gmail account
Tap Delete Account
Confirm the deletion
If the account is the only Google account on the phone, add another account first if needed
If you want to keep the account on the phone but stop syncing, turn off sync instead of removing it