Just sign in at iCloud.com or use the Find My iPhone app to see your missing iPhone, iPad, iPod touch, or Mac on a map. And with the Lost Mode feature you don’t just see where your device is, you can track where it’s been. That way you can decide on your best course of action.
You can immediately lock your device and send it a message with a contact number.
Then whoever finds it can call you from the Lock screen without accessing the rest of the information on your device.
I have a sticker on my devices with a phone number so who ever find it can call me. There is a lot of honest people.