Two-factor authentication (2FA) adds an extra layer of protection to your online accounts. By requiring not just a password, but a second form of verification, 2FA makes it harder for unauthorized individuals to gain access to your accounts., even if they somehow obtain your password.
In HKMU, we implemented a 2FA system, powered by Duo Security, to enhance the security for staff to login sensitive online applications. A user is required to complete a simple Duo 2FA Self-Enrollment setup procedure. Then, the user can use his/her enrolled device to accept a push notification or get a one-time passcode to complete the second authentication challenge while logging to 2FA enabled applications.

A Self-services on 2FA can let staff to "Manage Enolled Mobile Devices" or generate a "Bypass Code" if you don't have the enrolled mobile device on hand when performing 2FA authentication.
To understand more about the 2FA service, access the User Guide and the FAQ on the 2FA service can help.