On our paid plans we support Two-Factor Authentication (TFA/2FA). We are supporting Time-based One-Time Passwords (TOTP) which require the use of an Authenticator app, such as Google Authenticator or Authy, and is also supported directly by several password manager apps.
We enforce TFA only when logging in using a password. When you login with Google, we do not require TFA.
You can enable TFA from the User Settings.