What are Free Spy Apps Available for Parental Control?

I have installed Hoverwatch free android keylogger on my kids phones and can recommend this app to you.

You remain invisible when using Hoverwatch free android keylogger : There is a feature of the tracker that lets you be invisible, totally hidden from the user. So even if your children are familiar with phones and how they work you’ll be able to see what’s going on in their phone undetected.