An illegal tackle by a player on an opponent results in a free-kick, or a penalty kick if the foul was adjudged to have been committed in the penalty area. A foul is awarded if a tackle is deemed to be unfair by the referee. These fouls are usually punishment-free, however, if the referee deems the offense to be a professional foul then a caution may be given.
Fouls can be awarded when an advantage is gained by using any physical contact, e.g. kicking or pushing an opponent to take the ball. A handball can also result in a foul being awarded however this depends on whether the referee thinks the offense is deliberate. If the referee awards a foul for these offenses then a direct free kick will be given to the attacking team, giving them a direct advantage to shoot at goal or start an attack.
However, in some situations, the referee will award an indirect free kick. This is usually for offenses such as goalkeeper violations, e.g handling the ball outside the penalty area or picking up a back pass from a teammate. Another offense could be time-wasting on throw-ins or other set pieces disrupting the match.