Sites and apps will be able to request your email address, but you can also opt to hide it. In that case, Apple will generate a random email address that forwards messages from those services to your regular inbox. You can disable those randomized addresses at any time. Sign in with Apple will work with the company's various devices as well as on the web.

You can authenticate your logins with Face ID or Touch ID, while Sign in with Apple has built-in two-factor authentication to make it more secure. Apple says it won't use the sign in option to track activity in apps or profile users.