Currently, Switcher Studio does not offer simultaneous streaming across different platforms from directly within the app. However, you can still use third-party services such as restream.io and switchboard.live to simulcast to multiple platforms while using Switcher Studio.
This blog post walks through the process of simulcasting using Restream or Switchboard.
While Switcher Studio doesn't provide simulcasting across different platforms, we do have an option to broadcast to multiple destinations on Facebook simultaneously. Check out this article for more information about Crossposting on Facebook.