Streaming can be tough to do the right way. If you want to stream on Twitch, you need to set up a program like OBS or Xsplit, customize a bunch of options to make things just right, and sometimes even pay for a few services to get all of the bells and whistles you need. In an effort to make streaming something that everybody can do without much know-how, Microsoft is letting gamers stream their gameplay straight from the Xbox Game Bar in the Creator's update.
The Game Bar already lets people record their gameplay without too much effort, but streaming is an all-new thing. The streaming option won't be going through Twitch, but will instead be going through Beam, a service that lets your audience interact with you while you stream. Unlike Twitch, the chat for Beam doesn't have a delay - you'll be able to interact with your audience in real time.