MFA (Multi-Factor Authentication) requires the users to identify themselves by more than a username and password. In practice this means that after entering your username and password, the sign in is further verified with the smartphone application (Microsoft Authenticator) you have linked to the service. It is the same principle as used for online banking.
The University of Jyväskylä uses multi-factor authentication (MFA) in Microsoft365 services. Follow these instructions to enable MFA:
Deploying Microsoft multi-factor authentication with Microsoft Authenticator application
Enabling Microsoft MFA with a security key (FIDO2)
Would you like to use the Microsoft Authenticator app on multiple devices? Are you switching to a new phone? With this guide, you can set up the app on more than one device. Microsoft Authenticator can be used simultaneously on your phone and tablet. This guide can also be useful if you are switching to a new phone. Please note that the old phone is needed during this setup process.
Deploying Microsoft MFA on another device
Has your phone broken or gone missing? To get the Microsoft Authenticator app working on a new phone, you need to reset MFA first. Resetting may also be necessary if the app stops working for some reason.
How often multi-factor authentication approval is requested?
How do i unlock an application in Microsoft Authenticator?
Deploying Microsoft multi-factor authentication for Teams visitors
Multifactor authentication - Frequently asked questions