Access the Find My iPhone application from a computer by going to iCloud.com/find, as of June 2015. After logging in, you can view a map with the device's location, play a sound on the device, put the device into lost mode or erase all your information from the device.
Find My iPhone must be set up on the device before it can be used. The application is available for the iPhone, iPod Touch, iPad and Mac computers.
When using the map feature, the device's approximate location or last known location is displayed. A green dot indicates the device is online, while a gray dot indicates it's offline.
Lost mode locks the device. You can still track it in lost mode. However, if you remotely erase the personal information, you can't use Find My iPhone anymore.