When would a football team decide to punt?

Answer 1

If the team is down to their 4th down and have yet to make the 10 yards to get to 1st down again, a team would either set up for a field goal if they are in range, or simply punt the ball instead of attempting a 4th and long.

Answer 2

A team would decide to punt the football in their final down. They would punt the ball to relinquish the ball if the team is struggling to win the game.