In iOS for testing you can use Testflight . As for Android there is an option to publish your testing app, there are 3 different ways: Production APK , Beta testing and Alpha testing .
In which you decide at what moment you leave the testing to be able to publish a apk production, I put an screenshot :
To this I was referring to the 3 phases, the green circle is the part where you place your APKs for production, which has already been tested by the users and with the changes that you have personally added or the change set aggregates suggested by your users:
It is recommended to start with a small group of Alpha testers and then expand your test to a larger Beta test group.
Closed Beta Test: Consider using closed Beta tests for a smaller group, such as within your company or team, or when you have already determined the exact users you want to test your app. If you want to try an app that you previously published, only users within the trial group will receive an update for the Alpha or Beta version.
Open Beta Test: Consider using open Beta tests for a larger group and publishing the Beta version of your app in the Play Store. If you do an open Beta test, any user can join the Beta program and send you private comments. Before choosing this option, make sure your app is ready for publication in the Play Store.