Back during the Worldwide Developer Conference (WWDC) 2019, Apple announces a new secure way of signing into your social accounts called Sign in with Apple. Looks like now, Apple is testing another method to login into the iCloud.com. This is first reported by 9to5Mac where the users who have iOS 13 beta running on their device able to sign in into the iCloud via Face ID and Touch ID. Even macOS Catalina also supports this feature.
To try this feature, you have to visit the iCloud.com beta url using your beta devices. Once you try to enter your user credentials, a pop-up shows whether you want to sign in into iCloud using your Face ID or Touch ID. It seems, through this method, we might not require to use the two-factor authentication anymore. Normally, once signing in to the iCloud, a code will be sent to your iPhone where you have to enter it into your iCloud account. This time it wouldn’t be necessary anymore.
In conclusion, Apple believes this could be secure and trustworthy to implement with the Sign in with Apple feature. Apple might remove this feature too during the final release. Let’s wait for further confirmation from Apple.