How to spy on someone’s cell phone?

Here’s an easy formula to spy on someone’s cell phone – install spyware on a target device. It allows spying on a cell phone without taking it into hands. However, to have it set up on the device, one-time physical access is a must.
The installation process depends on the target’s operating system. Thus, to spy on an iPhone, users need to find out another person’s Apple ID and enable its iCloud backup. To spy on Android devices, they have to take a phone and install spyware on it. The further monitoring is being performed remotely without another person knowing about it.