Top bar allow to display extended content ex. contact information, social icons etc. above main menu area, To enable it open Appearance > Customize > Navigation > Top Bar
If you enable “Top Bar” you can setup social media profiles you want to display via Theme Setting > Social Profiles.
There are options to change the top bar background color, font color and border color too. Simply click on the colorbox to open color picker panel. Select color you want and once finish customising, save changes.