Two-factor authentication (2FA) or Multi-factor authentication (MFA) strengthens access security by requiring two (or more) methods (also referred to as factors) to verify your identity. These factors can include something you know - like a username and password, plus something you have - like a smartphone app to approve authentication requests.
Attacks on accounts are increasingly sophisticated. 2FA helps to determine that you are who you say you are and are not someone with a stolen password.
UC uses the Duo 2FA service to help protect data with Two-Factor Authentication. You may be required to use Duo before you can use certain UC services, including Office 365. You can set up Duo on multiple devices.