How do you disable taskbar and menu bar in mac OS.

I am trying to use an app called shadow that allows you to stream a high powered desktop but when I use it and go to the top of the screen or the bottom when I am in full screen mac annoyingly unhides the menu. This is annoying especially when there is an exit on the top of the screen and I press the three lines. Is there a way to turn off the unhide while in full screen mode??? I honestly dont really care if it changes the way mac OS operates I mostly use the Windows on my shadow box.