Hello eka106,
Thanks for posting to Apple Support Communities.
We're happy to help. We understand that you're trying to track your lost iPhone.
See here: Locate a device in Find My iPhone on iCloud.com
If the device can’t be located: You see Offline below the device’s name. The last known location is displayed for up to 24 hours. Select “Notify me when found” to get an email when it’s online again.
Note: If you turned on the Find My network, you can use the Find My app on any device that’s signed in with the same Apple ID to see your device’s location, even if it’s offline. The last known location is stored for up to 7 days.
This article helps explain what can be done as well: Use the Find My app to locate a missing device or item
That should help. Let us know if you have any questions.
Take care.