To enhance the security of your account, enable two-factor authentication (2FA) or Two Factor Authentication. Log in with your smartphone.

To activate two-factor authentication, go to your user profile page (click on your email address in the top menu):

Install "Google Authenticator," "Authy," or a similar authentication app on your smartphone, then scan the QR code.

Enter your verification code and activate two-factor authentication.

The next time you log in, you'll need to enter your verification code again to sign in.

You can easily disable two-factor authentication via the user profile page.