They removed the Search and other Nav Extras for the Genesis Framework (v2.1) a while ago, but you can give this link a try if you want to set it up – https://my.studiopress.com/snippets/nav-extras/
Other Tutorials that show how to do it – https://www.google.com/search?q=add+search+to+genesis+menu+2017&oq=add+search+to+genesis+menu+2017
