Module 1 of StartCloud's Microsoft 365 Security Essentials learning pathway, in six short units with a knowledge check: what MFA is, the three ways to run it in Microsoft 365, how to choose, and the exact steps to switch it on.
How to Turn On Multi-Factor Authentication in Microsoft 365
Why passwords alone stopped being enough
Here is the uncomfortable truth about passwords: yours has probably already leaked somewhere. Breaches happen constantly, and people reuse the same password across a dozen sites. If a scammer gets one, they will happily try it on your Microsoft 365 login too.
Multi-factor authentication (also called MFA, two-factor, or 2FA) closes that door. It asks for a second proof of identity at sign-in, usually a quick tap on your phone. Microsoft rates it as the number one way a business can protect its data, and after years of cleaning up accounts that did not have it, we wholeheartedly agree.
Think of MFA like the second latch on a hotel room door. It will not stop a determined ram-raid, but it absolutely stops the person who found your key card in the lift. For the overwhelming majority of real-world attacks, that second latch is the whole game.