Why this matters
Your Microsoft 365 account gives access to your email, files, Teams chats and often your whole business. If someone steals your password, multi-factor authentication (MFA) stops them signing in without your phone. Microsoft reports that MFA blocks the vast majority of account compromise attacks.
What you'll need
- Microsoft 365 account
- Mobile phone
- Microsoft Authenticator app
Step-by-step instructions
Step 1
Install Microsoft Authenticator
On your phone, download Microsoft Authenticator from the App Store or Google Play. Check the publisher is Microsoft Corporation.
Step 2
Sign in to your Microsoft 365 account
On a computer, go to mysignins.microsoft.com and sign in with your work email and password.
Step 3
Open Security info
Select "Security info" from the left-hand menu. This lists the sign-in methods on your account.
Step 4
Add a sign-in method
Select "Add sign-in method", choose "Microsoft Authenticator" and select "Add". Follow the prompts until a QR code appears.
Step 5
Scan the QR code
In the Authenticator app, tap the + button, choose "Work or school account", then "Scan QR code". Point your camera at the code on screen.
Step 6
Approve the test notification
Microsoft will send a test notification. Enter the number shown on your computer into the app and approve it.
Step 7
Set Authenticator as your default
Back on the Security info page, set "Default sign-in method" to "Microsoft Authenticator – notification". Consider adding a phone number as a backup method.
Troubleshooting
I am not seeing the Security info page
Your organisation may manage MFA registration for you. Contact your IT administrator, who may need to enable registration or reset your methods.
I got a new phone
Add the new phone in Security info before wiping the old one, or ask your administrator to require re-registration of MFA methods.
Frequently asked questions
Is MFA free with Microsoft 365?
Yes. MFA with the Microsoft Authenticator app is included with all Microsoft 365 business plans.
What if I lose my phone?
Contact your IT administrator. They can require you to re-register MFA so you can set up the app on a new device.
Summary
With MFA enabled, a stolen password is no longer enough to get into your Microsoft 365 account. It is the single most valuable security step for any business using Microsoft 365.
Still Need Help?
Some IT problems are easier to solve with a professional. If you've followed the guide and still need help, the Omnicron team can assist.