App Drawer is the place where all of your apps are stored on the home screen, and also where they can be found in other places like inside folders or search results.
Note: The App Drawer is one of the features that distinguishes Android from other mobile operating systems. It works as an easy way to access all your apps and services across different screens, even if they’re placed in folders or hidden inside search results.
It can be customized to display widgets, apps or shortcuts on the home screen. Each custom Android ROM has its own App Drawer.