Stick or remove menu bar

Hi,
I’m having issues with the Emag theme, the menu bar follows the screen upon scrolling but it doesn’t do it gracefully in my opinion and on a smartphone it’s even worse. I would like, ideally, to stick it so it doesn’t move any more, or completely remove it. I’ve tried to get into the header.php but I get a lot of errors when I erase the code. Is there a simple ways of doing it ?

The same goes for the Footer bar, that adds itself when the page is scrolled down, if this was possible to stick it that would be nice as well.

Thank you in advance for your help.