If you want to monitor an iOS device, such as iPhone, iPad or iPod Touch, you just need to know the iCloud account on it. But when you are monitor and Android phone or tablet, you need to install the App on it secretly.
Using FoneMonitor won't require root or jailbreak on the target devices.
FoneMonitor supports iOS (iPhone, iPad, iPod Touch) running iOS 10.0.0 or higher, supports Android phones or tablets running Android 4.0 or higher. Preview more supported devices on FoneMonitor Compatibility Policy.