https://thenextweb.com/apple/2019/06/03/apple-introduces-privacy-focused-sign-in-with-apple-button-for-sites-and-apps/

Apple addressed privacy problems by calling out trackers around the world at its WWDC developer conference. To address that, the company introduced a new sign in method: Sign in with Apple.

Just like ‘login with Google’ and ‘login with Facebook,’ you can sign in into an app by ‘login with Apple‘ button. It uses FaceID for authentication, and creates a new account if you don’t have any.