Introduction
Two-Factor Authentication adds a layer of security by adding a second step to the login process. It takes something you know (for example, your password) and adds a second factor, typically something you have (such as your phone). Since you require both to log in, this decreases the threat of a leaked password.
Setting up of Google Authenticator
Follow these steps:
https://support.google.com/accounts/answer/1066447?co=GENIE.Platform%3DAndroid&hl=en