While developing an Android app, you would usually run it on a physical device or an emulator. If you want to share it with someone for their feedback, you would share an APK that can easily be installed on any Android device.
Notes
- This APK can only be used for testing. For deployment, you should generate a signed APK for which the process is a little more complicated.
- You need to enable the “Allow unknown sources” option in the settings of the device where you want to install the APK.