Two-factor authentication keeps your account more secure by requiring both your password and your phone to login.
When you log in with two-factor authentication enabled, you will need to enter both your password and also a unique code generated on your phone. This provides a second layer of protection on your account. Even if someone knows your password, they won't be able to access your account without also having your phone.
Please visit the two-factor authentication settings page to set up two-factor authentication for your account.