Web authentication API is now supported by the latest versions of popular browsers including Microsoft Edge, Google Chrome and Firefox. It allows users to sign in to websites that are compatible with WebAuthn using physical security keys.
Mozilla has said that it will add support for Windows Hello in Firefox 66 to further enhance password-less login experience for users. If you use Windows Hello to sign in to your Windows 10 device using facial recognition, fingerprint sensor, FIDO2 security device or PIN, you’ll be able to sign in easily in Microsoft services in Firefox 66.
Facial recognition and fingerprint sensor could be used for signing into Microsoft services like Office 365, OneDrive and Outlook.com.
J.C. Jones, the web authenticator editor for Mozilla, said in Bugzilla some time ago:
“WebAuthn no longer works on Windows Insider builds, as compatible security keys are no longer available via the USB HID interface. (Basically, u2f-hid-rs  will stop supporting Windows 10+). Sometime this spring, Firefox 66 or 67 (and ESR 60) will need to use the Windows Hello API on when available to interact with Web Authentication. Otherwise, no devices will be detected, and we’ll have a Windows feature regression.”
Now the bug has been resolved, and Mozilla is aiming to bring the Windows Hello support in Firefox 66.