Are you asking about Find my Phone function that allows you to locate the device when you lose it?
Unfortunately, you should have enabled the application before the loss to have the ability to located the device. If you did:
Login into your iCloud account on another system and select Find iPhone.
Click All Devices to see all the machines enabled for the service.
Search for the wanted device.
You should see the map with the pinpoint of the location and you can also click Play Sound option if you see the device near you, but cannot find it particularly.
Are you asking about Find my Phone function that allows you to locate the device when you lose it?
Unfortunately, you should have enabled the application before the loss to have the ability to located the device. If you did:
Login into your iCloud account on another system and select Find iPhone.
Click All Devices to see all the machines enabled for the service.
Search for the wanted device.
You should see the map with the pinpoint of the location and you can also click Play Sound option if you see the device near you, but cannot find it particularly.
Good luck,
UGetFix team