Answers

@technonicx user It can also be installed remotely. It is likely to be malicious software embedded in any APK you install. If you have an old device, it may have been installed on your device over a WiFi without your knowledge. If you want a more utopian scenario, there is a possibility that it may have leaked to your device with an open for Android that has not been closed yet.

@technonicx user It may even have entered due to any software you downloaded. It doesn't happen physically.

@technonicx user efedesu said:

@technonicx user Installing from the Play Store didn't matter much. It can be released even in million + downloaded applications.

@technonicx user I am using Galaxy A7 2018 since I sent my phone to the service. I'm not so old right now I'm on Android 9. rtpc said:

Maybe you are insterested