With a HomeKit Secure Video camera or doorbell, you can use the Home app to receive notifications when people you’ve tagged in the Photos app come to your door.
Face Recognition identifies people by the faces that appear in your photo library or pictures of recent visitors captured by your camera or doorbell.
If you’re setting up a camera or doorbell for the first time, do the following:
Go to the Home app on your iPad.
With Face Recognition turned on, tap Set up accessories with Home on iPad