After an installation the app on to device of target users (your children, your employees), you can hide the icon of the app and start to track all the activities with the website of user control panel (or with server app if you do not want to use the website to view the data logs).
However, there are some cases, the app will be removed from the device without you know. Here are general cases:
I. Google Play Protect app.
The target app which you install on to the device, normally it asks some permission from Android Operation System. It checks all installed applications and then maybe it will make stop working or even force (automatically) an uninstall with our app.
How to disable Play Protect:
Disable checking application otherwise the risk of uninstalling the application:
The important step of the application to stay alive and to ensure that the application is not stopped and work properly:
1) Open Setting ==> Google (Google Service)
2) Tap Security ==> Google Play Protect
3) Turn Off Scan device for security threats
4) And it is OK.
Reference: for more details you can read this article https://mobileleak.com/how-to-disable-google-play-protect-on-android-devices/
II. Check other configuration
There are some configurations on Android device you should check to make the app still be alive.
1. Activate all permissions
Activate the permission necessary for the proper functioning of the application.
2. Do not optimize battery usage
This makes it possible to keep the application running in the background to ensure that the application is not stopped.
3. Device administrator
Administrator rights prevent the application from shutting down, locking the phone, erasing all data, and block the camera.
III. Check if you hide the icon of the app
Sometimes you forget to hide the icon of the app so that the target user will see the icon and then he can launch the app and know what happened.
How to show/hide the icon
IV. Check other essential settings
Please read this article for more details:
V. Target users can remove the app themselves
If target users know a little about technique, they can understand what happened and then, they can remove the app.
So, after configuring all such as do an authentication (login on device that means you attached the device to your account already), hide icon, wait a moment and can see the app work with some data sent to the server (the user control panel), you should clear browser history where you can access the links (link how to install, link about product...).