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. More importantly, you can choose to hide your email address, and Apple will generate a random email ID visible to only to that particular app that’ll forward all emails to your main email ID. Plus, this method creates a unique random email for each app, so that they can’t track you and your personal data.
— pixelomer (@pixelomer) June 3, 2019 The new sign-in feature is available across MacOS, iOS, and websites. This is an important feature for users who care for their privacy, especially after recent reports of apps tracking your data.