I will simplify the question:
I want to launch an external application at a time that I developed.
Intent launchIntent = getPackageManager().getLaunchIntentForPackage("com.mariana");
startActivity(launchIntent);
and with this code I open the application.
My question is how I now close that application that is external to the one I am developing
One option is to implement code in the application so that upon receiving a value in the bundle, determine to close the application.
For example
Intent intent = new Intent(MainActivity.this, MainOtraApp.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("cerrar_app", true);
startActivity(intent);
when receiving the value in the bundle that determines to close the application
if (getIntent().getBooleanExtra("cerrar_app", false)) {
finish(); //Cierra Activity.
}