iCloud: Find My iPhone overview
Locate your device on a map
Play a sound on your device to help you find it
Use Lost Mode to lock and track your device
Remotely erase all of your personal information from the device
Get started with Find My iPhone
First, you need to set up your device. Then, you can use Find My iPhone from any computer at icloud.com/find, or download and use the free Find My iPhone iOS app on an iOS device. When using Find My iPhone from a computer, make sure you use a browser recommended in the Apple Support article System requirements for iCloud.
Find your family members’ devices
If you joined Family Sharing, you can use Find My iPhone to help find and protect any family member’s iOS device (iOS 8 or later), Apple Watch (watchOS 3 or later), and Mac computer (OS X v10.10 or later). First, each family member needs to set up their devices to share their locations with other family members. For more information, see the Apple Support article Family Sharing and location.
Learn about Activation Lock
When you set up Find My iPhone, Activation Lock is turned on automatically. Activation Lock makes it harder for anyone to use or sell your iPhone, iPad, iPod touch, or Apple Watch if it’s ever lost or stolen. For more information, see the Apple Support article Find My iPhone Activation Lock.