To create a menu item that will display content to your menu dropdown. Go to Envy Mega Menu->Add New. Now you can build your mega menu with Gutenberg or Elementor editor. We recommended using the Elementor plugin.
Build your menu content using the editor.
After finishing go to Appearance->Menus and enable Envy Mega Menu from Screen Options.
Now add your created menu to any submenu where you want to display it.
Note: It only works as a droupdown item.
Now you can check your site menu: