When I scroll Up on mobile I want to show the header of the website.

Hello,

You need to enable the sticky header. This option would be applied to both desktop and mobile, there is no option to set it on mobile only. if you still need it on mobile only, I can hide it with custom CSS on the desktop: https://xtemos.com/docs/woodmart/header-builder/enable-sticky-header-option/

Please add this code to the Theme Settings > Custom CSS > Desktop:

body .whb-sticked .whb-general-header {
   display:none;
}

Best Regards