This is not a solution per se but a trick that works for many people. If this isn’t the case, continue with the next solution to resolve the Taskbar does not hide when on full screen mode issue on Windows 10. The taskbar will be hidden now and you can access it by hovering down.
It will automatically hide the taskbar when you are in desktop mode and appears back as you hover mouse down. You can hide your Taskbar on the Desktop mode by changing taskbar settings.
2] Turn on the Automatically hide the taskbar in desktop mode
