If you misplace your iPhone, iPad, iPod touch, or Mac, the Find My iPhone app will let you use any iOS device to find it and protect your data. Simply install this free app, open it, and sign in with the Apple ID you use for iCloud. Find My iPhone will help you locate your missing device on a map, remotely lock it, play a sound, display a message, or erase all the data on it.
For missing iOS devices, Find My iPhone also includes Lost Mode. Lost Mode locks your device with a passcode and can display a custom message and contact phone number right on the Lock Screen. While in Lost Mode, your device can keep track of where it has been and report back so you can view its recent location history, right from the Find My iPhone app.
Please note that Find My iPhone must be enabled in iCloud settings on your device before you can locate it with this app.