Header settings are located in Appearance → Customise → Header Settings.
Activating the Make navigation bar sticky option will make navigation bar visible when scrolling.
By activating the Enable the smart sticky feature navigation bar will be revealed when scrolling up and hidden when scrolling down. The feature allows to save viewport space when viewing your website.
You may enable social links in the header by activating the Display social links checkbox.
You may disable search button in the header by deactivating the Display search button checkbox.