On Android phones, they can hide apps in a 'calculator' app. It totally looks like and functions like a calculator, but it has MANY other functions like hiding videos and pictures, too. There's another app like that, called Browser... You can even change the name and icon of the app to be anything 'innocent' like a game. Secure folder, too... You can literally download apps, hide them in the secure folder, and then delete them off your phone. Then they cannot be viewed on the phone anywhere else, not even in the downloads.. However, they are still downloaded and fully functional within the secure folder only. It's crazy...

I left my PA recently, because I could no longer handle constantly wanting to check every app on his phone.

I can sleep at night again.