Q: Have an iphone 5 second hand, no idea who and what the id and password is

Return it to where you bought it and ask for a refund.

Without the apple id and password the iPhone is useless to you. There's nothing you can do to unlock it.

iPhones must be cleared of the original owner's information and reset to factory defaults before they can be passed on to a new owner. Take the iPhone back to the Community Store and ask if they can do that or if they can get the original owner to do it. If they can't ask for a refund.

The original owner needs to follow these steps before passing the iPhone off to a new owner.

What to do before selling or giving away your iPhone, iPad, or iPod touch - Apple Support