Before I start, I guess you are unaware about this feature as an average gmail user. It’s step 2 verification for Gmail login. Google going beyond the username and password in this step. Once you have activated step 2 verification, ordinary login details will not be enough to access your gmail account. Google will send a verification code to your mobile phone when you enter gmail login details and in the secod step you will have to enter that verification code to login gmail account. That means hackers will no longer be able to have unauthorized access to your Gmail account anymore without your mobile phone.
It really simple to activate step 2 verification on your gmail account.
1. login gmail account using ordinary gmail login details
2. Click on the username at top right
3. click account
4. select security tab on left sidebar
5. Click edit in front of step 2 verification
6. Activation process will start with following screen
Then you will be taken through guided few steps setup wizard. Select the method you want to receive the verification code. (SMS or Voice call to given number). Also you will have to setup a backup plan to login Gmail account when your phone is unavailable. Home, friend’s or any trusted phone number could be set to receive verification code alternatively when you primary phone number is not available.
After everything done successfully, You are ready for first run of Gmail step 2 verification. Just sign out all google services and go to gmail website. Enter regular gmail login details and then you will receive a text message or voice call to given phone number. Likewise you will be prompted to enter the verification code instead of displaying inbox. Now accessing to gmail account is only possible who has your login details and your mobile phone. It’s a rare case someone has both of these without your permission.