To help streamline the log in process, many websites offer integrations with services like Google, Twitter, Apple, Facebook and more, to allow visitors the chance to log in with existing credentials for the other services. To provide that option, the design requires a few additional buttons, depending on how many of these services will be available.
For the purposes of this tutorial, Google and Apple will be used as single sign on partners. Creating the buttons is as easy as creating the log in button. Both Apple and Google have guidelines on how to label and design these sign on buttons.