How to Find Your Lost iPhone
Find My iPhone" app can help you in locating your iPhone incase it is lost or you have misplaced it. You simply need to activate the app in your iPhone Settings. Go to Settings – tap iCloud – Enable Find My iPhone.
Incase you misplace your iPhone, you will need to sign up to icloud.com and it will show you a map of where your iPhone is located or you can locate it by use of "Find My iPhone" from another iPhone/iPad.