Social Login.
Federation to consumer-grade identity providers (Google, Apple, Facebook, Microsoft, GitHub) that lets users sign in with an existing account rather than creating a new password.
Sign in with Apple has unique requirements: iOS apps that offer any third-party social login must offer Apple as well. The privacy stance (private relay email, no tracking) is meaningfully stronger than other social IdPs and worth surfacing as a deliberate choice for privacy-conscious consumers.
Common questions
Is social login the same as SSO?
Should I support Sign in with Apple?
What user data do I get from social login?