> At your first sign in, apps and websites can ask only for your name and email address to set up an account for you. You can use Hide My Email—Apple's private email relay service—to create and share a unique, random email address that forwards to your personal email. That way you can receive useful messages from the app without sharing your personal email address. Only the registered app or site developer can communicate with you using this email, and you can turn it off at any time.

> Sign in with Apple won’t track or profile you as you use your favorite apps and websites, and Apple retains only the information that’s needed to make sure you can sign in and manage your account.

From https://support.apple.com/en-us/HT210318