On Android phones you can just toggle a setting to allow apps from outside Google Play and then install whatever you want however you want. You can e.g. send yo

On Android phones you can just toggle a setting to allow apps from outside Google Play and then install whatever you want however you want. You can e.g. send your program over FTP or Bluetooth and click the APK file to install it. Or you can use F-Droid with a repository of your choice: https://f-droid.org/ https://f-droid.org/ Note that the permissions system, app signing (with any key as long as it's the same for subsequent versions of the app) and other safety features are built into the system so they still work the same - security it not dependent on the Play Store.