PhoneSheriff Investigator is no longer recommended because they have changed their product so that the app's icon is always visible, making their products not hidden anymore. The app is displayed on the phone's screen, and it will notify the user that the device is being monitored.
If you are looking for a Completely Stealth spy and monitoring app, check out our recommendations below:
1. For iPhone and Android
Highster Mobile Spy - The company was founded in 2010 in the United States and has since become a leading provider of cell phone spy software; Great features; Simple and easy to set up; No rooting & jailbreak required; One-time charges of $69 (No monthly fees!).
Visit their website: http://www.highstermobi.com
2. For Windows and Mac
Hoverwatch is the most popular powerful computer spy software that allows you to monitor EVERYTHING users do on their computer – in total stealth. With the ability to log all keystrokes, track web and program usage down to the second, and show you everything that has happened with screenshots, this software helps you learn the truth and put your mind at ease!
Visit their website: http://www.hoverspyapp.com
These applications run in the background of the phone without the user ever finding out. They all work as advertised, and they all offer a solid support team to help you every step of the way.