By default, the Divi Theme shows the same menu items in both the desktop and mobile versions of the header menu (albeit with different formatting). If you'd like to exclude certain items from showing up in the mobile menu, i.e. making them appear on the desktop menu...
mobile header
Show Divi Header Social Icons on Mobiles
Divi includes an option to enable social media icons in the secondary header. However, ever since v2.4, it no longer displays these icons in the secondary header on mobile devices / screen widths, even with the option enabled. If you'd like your mobile users to see...