This page explains how to host APKThe Android Package format output by Unity. An APK is automatically deployed to your device when you select File > Build & Run. More info
See in Glossary expansion files so they are accessible by the application.
Google Play can host APK expansion files for applications in their store. If an application includes APK expansion files, Google Play automatically downloads them to the device when the user downloads the application. This means if you deliver your application to Google Play, publish the APK expansion files along with the main APK, and Google Play handles everything.