The ball has gone "in touch" and the restart is a throw-in.
In professional soccer when the ball goes outside of the lines it is out of bounds.
Before, if the soccer ball went out of bounds, the first person to get to the ball obtained possession. This is why the sidelines are called the touchlines.
When the ball carrier is tackled and does not pass ball to teammate or the ball is out of bounds, the play is called a scrum, and the yard line where the last play was downed is called the line of scrimmage. -----In American football, draw a line from sideline to sideline where the ball is put into play on each down and that is the line of scrimmage.
You cannot kick a soccer ball out of bounds and still play it. If the ball is kicked out of bounds you either do a throw in, corner kick, or goal kick, depending where you are on the field.
They throw it in.
A ball girl in soccer would get the ball when it goes out of bounds and will give it to either the coach - referee and/or put it by the goal post out of bounds so that when a ball goes out again the goalie can just grab the ball that is by the post.
Noooooooo, they must step on or out of the actual line.
The ball is not "out of bounds" unless the ball or the player who possesses it touches the ground in an out of bounds area. So in the case where the ball is in flight over the sideline, and a player who is inbounds catches it and demonstrates control before stepping out, the pass is complete.