A field goal is worth 3 points. It is a timed special teams play. Field goals almost always happen on fourth down, as a last try to get points from a drive. Teams should only kick field goals if they are within field goal range. However, field goals can be attempted from anywhere.
The extra point kick is worth 1 point. An extra point kick is one of two options for a team when it comes to their try, which happens after they score a touchdown. The extra point kick is an untimed special teams play. The ball is snapped from the 15 yard line for an extra point kick.