
Quick Answer
Go to Microsoft’s Security Info page, sign in with your Microsoft 365 account and add Microsoft Authenticator as a new sign-in method.
If you have changed your phone, installed Microsoft Authenticator on a new device, or simply need to update the way you approve Microsoft 365 sign-ins, you can normally do this yourself.
Before you start, make sure Microsoft Authenticator is installed on your iPhone or Android phone.
On your computer, open the Microsoft Security Info page using the link above.
Sign in using your Microsoft 365 email address and password.
Click Add sign-in method.
Select Microsoft Authenticator and click Add.
Follow the instructions until a QR code appears on your computer.
Open Microsoft Authenticator on your phone.
Tap the + button and select Work or school account.
Select Scan QR code.
Scan the QR code displayed on your computer.
Microsoft will send a test notification to your phone. Approve the notification.
Once Microsoft confirms that the setup has been successful, Authenticator is ready to use.
This is Microsoft's current process for adding Authenticator to a work or school Microsoft 365 account.
If you are replacing an old phone, do not remove the old authentication method until you have tested the new one.
Once Microsoft Authenticator is working correctly on your new phone, return to the Security Info page and remove the old device or authentication method.
If Microsoft asks you to approve the sign-in using a phone you no longer have, you may not be able to update the authentication settings yourself.
In this situation, contact your IT administrator. They can reset your authentication methods or provide another secure way for you to register your new device.
Microsoft Authenticator provides an additional check when somebody tries to access your Microsoft 365 account.
Even if somebody discovers your password, they would normally still need to pass the additional authentication check before they can access your account.
Multi-factor authentication is an important part of protecting Microsoft 365 accounts from compromised passwords and unauthorised access.

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