What is Menu icon and Menu superscript title
Menu icon is the icon which normally we can see along with menu name. It is based in Fontawseome 4.7 . Hence you can select those icons only which are there.
Menu superscript title is the title which is just above the menu name. It can be any title you want to keep.
How to apply above features in your website
Step1. Go to appearance >> customize >> menu
Step2. Open screen options and there you can find checkbox named as Title attribute and CSS classes. Select these two checkboxes.
For menu superscript title , open the menu in which you need to add superscript title and write the title in the place defined under ” Title Attribute”. Then save the menu.
For menu icon, open the menu in which you need to add icon and write the icon class name in the place defined under ” CSS Classed (optional) “. Then save the menu. The class of icon you can get from here for example : fa-home . via fontawsome 4.7 . During adding such class name , do not forget to add full class name such as ” fa fa-home”. Need to add fa in the beginning as well.