In Short

Find my iPhone, sometimes also called Find my iPod, Find my iPad, or Find my Mac when referring to the same app running on those devices, is both a free service and app offered by Apple. The service is available on all Apple devices as part of iCloud. When you setup a new Apple device, it'll be offered to you and, if you accept, Apple will start to track your device. That means, if your iPhone, iPod touch, iPad, or Mac is ever lost or stolen, Find my iPhone can help you get it back.

To do that, however, you need to download and install the free Find my iPhone app on iOS, or go to on a web browser on the Mac or any PC. Once a device is located, you can remotely message is, have it make a sound, lock it, or wipe it entirely. With Activation Lock, Find my iPhone can even prevent a this from disabling the service. If you have an Apple product, you should be using it.