You've probably stumbled upon this researching how to remove the Xbox Game Bar. This gist includes a few different methods you can try. Please note that some of these first options are probably not be available unless you are running an older version of Windows 10.
(this is no longer an option on any recent Windows 10 build)
- Press Windows Key or click on the Start menu.
- Start typing
Game Bar, until you get the Xbox Game Bar app to appear in the results.
- Right-click on the app and pick
Yesto the prompt, and wait for the process to finish.