...
Follow this link: https://mysignins.microsoft.com/security-info to the “Security Info“ page and press the “Add sign-in method“ button.
Select “Authenticator App” from the drop box and follow the instructions on screen.
Then click Next on this screen
Then click ‘Next’ on this prompt that shows
On your mobile device, open the Apple App Store or Google Play Store, search for and install “Microsoft Authenticator” by Microsoft.
iOS: https://apps.apple.com/au/app/microsoft-authenticator/id983156458
Android: https://play.google.com/store/apps/details?id=com.azure.authenticator
Then click Next on this screenOpen the Microsoft Authenticator app on your mobile device. Allow Notifications if prompted.
If you see a “Scan a QR code” button, click that.
Otherwise,
you can go to Add Account by clicking '+' on top right corner > Work or school account > Scan QR code
Allow the Authenticator app to use the camera on your phone and then point the camera at the QR code on the your computer/laptop screen. Be careful to not allow other people to see/use this QR code.
After you successfully scan the QR code, your account will be added into the Authenticator app.
Click Next to continue.Microsoft will send a test notification to your Authenticator app for approval.
Approve this request on your mobile device once received
Then click Next on this promptSome services at NIDA require you to change your default sign-in method to “Authenticator App - notification”. If your current sign in method is not “Authenticator App - notification”, simply click on the “Change” button next to the current default sign in method.
...