Fantasy Football is a game of both luck and strategy. This game puts you in the front office of an 'imaginary team' of your making. Players draft from a list of NFL players and select players from each offensive position as well as team defense and a kicker. They then compete against the other teams in their league each week by setting a lineup of the players they've drafted.
Each player receives points based on achievements in their performance like rushing yards or touchdowns. The amount of players selected per position, as well as the scoring, varies from league to league. Teams can advance to the playoffs and play for a chance to win their league's Super Bowl. Fantasy football forces an owner to make decisions in things such as free agency, trades with other teams in their league, and the release of players.
Daily or weekly fantasy allows you to play fantasy football in shorter time periods than a whole season. Owners draft or create a team every day or week, depending on what they choose. They match up with other teams each week or day and attempt to put the best team they can in their lineup each day/week.
Owners draft a team each year at the beginning of the season and besides free agency or trades that roster stays the same all season. Teams match up each week and compete to make the playoffs and to win the super bowl of their league.