There are seven offenses that result in a direct free kick if done in a manner the referee believes was careless, reckless, or using excessive force:
kicking or attempting to kick an opponent
tripping or attempting to trip an opponent
jumping at an opponent
charging an opponent
striking or attempting to strike an opponent
pushing an opponent
tackling an opponent
There are three more offenses that result in a direct free kick if any player does them, regardless of carelessness, etc.:
holding an opponent
spitting at an opponent
handling the ball deliberately (except the goalkeeper in his or her own penalty area)
A direct kick one of the eight restarts of a soccer match.
A direct free kick.
There are 10 direct free kick offenses and 8 indirect free kick offenses. They are outlined in the FIFA Laws of the Game.
The kick off is neither direct nor indirect, they are three different restarts. A goal may be scored from a kick off.
You cannot score an own-goal on a direct free kick. The restart would be a corner kick for the opponents.
A direct free kick is given for one of 10, specific, offenses. A penalty kick is given when a direct free kick offense is committed by a defender, against an attacker, within the defender's penalty area.
Charging an opponent is a direct free kick offense.
Yes. Anyone on the field can score a direct or indirect free kick.
An indirect free kick is when the kick is unintentional.
Only if the kick awarded was a direct free kick.
in order to score a goal, an indirect free kick must touch another player before entering the net. A direct free kick does not.
No a kick can not cause hemrroids.