iOS 15 Built-in authenticator
Passwords
Built-in authenticator
Generate verification codes needed for additional sign-in security. If a site offers two-factor authentication, you can set up verification codes under Passwords in Settings — no need to download an additional app. Once set up, verification codes autofill when you sign in to the site.
Apple - IOS 15 Update Information
New in iOS is a built-in authenticator app, just like Google own authenticator.
Within passwords, you can now scan a QR code to add two factor authentication (2FA) to the login process, creating more security.
Settings > Passwords > find the account you wish to use 2FA on > click ‘Set Up Verification Code” > Scan the QR Code on the screen and follow the on screen instructions.