Security keys can only be added as an additional method of MFA.
- Go to https://mysignins.microsoft.com/security-info
- Click ‘+ Add sign-in method’
- Select ‘Security key’
- Click ‘Add’
- Click ‘Next’
- Approve MFA sign in request with a previously registered method
- Click ‘USB device’
- Click ‘Next’
- Click ‘OK’
- Plugin your YubiKey and TAP the brass circle on the key
- Enter a pin code for the device
- Click ‘Next’
- Touch the Brass Circle on your YubiKey
- Click ‘Allow’
- Enter a name for your key
- Click Next
- Click Done
