Two-factor authentication is a functionality that provides identification of users by means of the combination of two different components: something the user knows and something the user possesses. In this case, the user knows his user name and password and possesses access to his phone or email account.
Another user must acquire your: username and password.
The use of two-factor authentication to prove one's identity is based on the premise that an unauthorized person is unlikely to be able to supply both factors required for access. When an authentication attempt is tied, both factors must be correct or the asset being protected remains blocked.