My son lost my wifes iPhone in the house, and the ringer was off, so we couldnt just call it. Fortunately, I remembered something about there being a Find My iPhone feature. I Googled a bit; went to icloud.com; signed on with my wifes Apple ID; clicked on Find iPhone; clicked on All Devices; clicked on the icon representing the phone; and then clicked on Play Sound.
Beep-beep-beep, said the phone. I found it! said my son. All is forgiven, my wife will surely say when she returns. Alas, that will be beyond my sons gratitude horizon, but at least my wife will have her phone back.