Click on this link to read how to "Use the Find My app to locate a lost or stolen device" --> https://support.apple.com/HT210515
- "Don't see your device? You might not have Find My [device] turned on. If your device is powered off, the battery has run out, or more than 24 hours has passed since its last location was sent to Apple, you also can't see your device's location."
-The chances of locating a device depend upon which features you selected in:
Set up Find My on your iPhone, Mac, and other devices - https://support.apple.com/HT210400#enablefindmy