When is a punt allowed in football?

Answer 1

The offense can punt the ball at any time (on any down not just 4th) from behind the line of scrimmage. Once they punt the ball the other team must touch it before they can touch it again. If the punting team touches the punt first it is downed at that very spot and given to the other team.

If a punt goes out of bounds it is given to the other team where it went out and if it goes untouched into the endzone it is put on the 20yd line and the other team takes over.

Anyone not just a player listed as a punter can punt the ball. In high school football it is common to line up in a shot-gun formation on 4th down and then have the quarter back quick punt the ball. This sometimes tricks the defense into thinking the offense is attempting to get a 1st down and they may not have someone back to run back the punt. It can also be used just in case the defense does line up in a normal punt return formation and then the quarter back makes a quick choice after taking the snap as to whether he will go for the first down or kick the ball away.

Answer 2

A punt attempt can be made on any down.