Find my iPhone in different countries

Not necessarily. There are a handful of countries that restrict the functionality of FindMy (notably South Korea). Otherwise, it's likely because the device is not connected to a network.

No. It will show even if you are on different continents.

Share your location

1. Open the Find My app and select the People tab.
2. Select Share My Location or Start Sharing Location.
3. Enter the name or phone number of the person you want to share your location with.
4. Select Send.
5. Choose to share your location for One Hour, Until End of Day, or Share Indefinitely.
6. Select OK.

Find friends and share your location with Find My - Apple ...

Not unless one of you is in a country where that kind of thing is restricted or prohibited by law.