Two-factor authentication (2FA), also known as Multi-Factor Authentication or MFA, works as an extra step in the process, a second security layer, that will reconfirm your identity. Its purpose is to make attackers' life harder, because even if they get your password, they will still fail to access your account without the 2FA code.
2FA works by binding your Two-Factor Authentication application (we recommend Google Authenticator) to your txbit account. Once it is bound, the Two-Factor Authentication application will generate a code every 30 seconds, which must be entered together with the account password to login into your account. No 2FA, no access to your account.