What is Spotlight on iPad – where are Spotlight icons displayed?
Spotlight is the search function in iOS.

It can be accessed from the Home screen by swiping down.

From Apple Support:


  Use Search on your iPhone, iPad, or iPod touch
  With iOS 9, Search lets you look for content from the web, your contacts, apps, nearby places, and more. Powered by Siri, Search offers suggestions and updates results as you type.
  
  There are two ways to use Search on your iOS device. 
  
  Quick Search
  
  Drag down from the middle of the Home screen and type what you're looking for.
  
  Siri Suggestions
  
  Drag right from the Home screen to show search and get Siri Suggestions.