You can use managed Google Play to distribute private apps. Private apps are apps, developed by you or a third-party, that are published to managed Google Play and only available to users in your organization. They aren’t listed in the public Google Play Store and aren’t available to users outside your organization to view or install.
The Android application package (APK) for a private app can be hosted by Google (similar to a normal app), or it can be self-hosted by your organization. In both cases, you must upload the app's store-listing metadata to managed Google Play.
For information on how to build internal private apps that work correctly with a managed profile visit Building apps for work.