If you use 2-Step Verification and you're having trouble signing in, you can have a verification code sent to your backup phone:
- Go to the sign-in page of the Google service you want to use (for example, Gmail).
- Enter your username and password.
- Select Try another way to sign in or More options.
- Select Get a verification code.
- Follow the instructions to enter the code you were sent. If you don't get a code, you can select More options Get help.