Phone found

Apple doesn't get involved in lost or stolen devices. Best advice is to turn it over to the local authorities and hope the owner filed a police report.

It's really great of you to want to get the phone back it its rightful owner!! Kudos to you.

It is at the owners discretion whether they put information on a lost mode screen for yo to contact them. If they chose not to do so, all you can do is drop it off at a recycling facility (Apple takes devices for recycling).

If there is no contact info on the phone you'll be unable to give it back. Keep it charged for a day or two and see if anything gets posted.