Use Find My --> Use the Find My app to locate a missing device or item - Apple Support
If Find My iPhone is offline or not working
https://support.apple.com/HT204233
If you see "Offline," "No location available," or "Location Services Off," your device might be offline for one of these reasons:
It's powered off, the battery has run out, or more than 24 hours passed since the last location was sent to Apple (if Send Last Location is turned on). When your device is connected to the Internet, you can see the remaining battery in the upper-right corner of the information pane.
Your Find My compatible device isn't connected to a known Wi-Fi or data network. Wait a few minutes and try again.
You're in a country or region where we don't offer this feature. This feature might not be available in your country or region due to technical limitations or local law.