phone disable, forgot passcode

Was this your iPhone you found or you just found an iPhone and it is disabled? If it is indeed your iPhone, you'll need to erase the phone using a computer by following the directions in this link --> If you forgot your iPhone passcode - Apple Support

If it is NOT your iPhone, and you found it, you won't be able to do anything with the phone at all. You would not know the Apple ID or Apple ID password used to set up the phone, so it would be totally useless to you.

Then follow the directions in the link (blue words) I provided. You will need to remember the Apple ID and Passcode you used to set up that phone in order to erase it.