For safety, privacy and security reasons, you can’t access everything from your iPhone using an Apple Watch. However, if you’ve invested in an Apple Watch, at least now there’s a way to open it while wearing a mask.
In order for it to work, Face ID needs your eyes, nose, and mouth to be visible. With a mask, that isn’t possible.
First, you have to have a Series 3 or newer Apple Watch to unlock your iPhone using an Apple Watch running watchOS 7.4 and up.
Second, if you’re running iOS 14.5 and up, on your iPhone, you can authenticate yourself using that Apple Watch.
The process is very similar to how Mac owners unlock their computers using Apple Watch. Just make sure your Watch’s on-device lock screen is unlocked, and that device is within Bluetooth range. That’s how you bypass the Mac’s login process.
Remember though, you still cannot authenticate Apple Pay or App Store purchases using this authentication. Also, if your iPhone doesn’t recognize you using Face ID, you’ll must still enter your Apple ID password or lock screen passcode.