First, the question is whether YOU can legally own a gun, and if you have a right to keep the one you found (Finders Keepers is not legal advice). Then the question becomes whether you need to register it- in the US, there IS no Federal registration of ordinary guns, and MOST states do not have registration. Your smartest course of action will be to contact law enforcement, and arrange for them to hold the firearm until the three questions I asked get answered.
If you're in the U.S. the short answer is, you can't.
MOST US states do NOT have a requirement to register firearms. Those that do, the records are not open to the public.
First, find out if there is a process to register guns where you are. There is no gun registration in most of the US. If registration IS required, then check with the agency that handles that.
You would have to go to your local gun shop and register your firearm there. Then, after completing that, you would have to go the gun range and register yourself there, with your gun permit.
Depends on where you are. In MOST of the US, there is no requirement to register an ordinary firearm. There is also no place to register a gun- on line or otherwise.
Depends on what state you are in. In MOST of the US, there IS no requirement to register a gun.
No
No.
No
no
Texas does not require gun registration.
No,