The bowler's crease is a line marked on a cricket field that indicates the area where the bowler must deliver the ball. It is located at the bowler's end of the pitch, parallel to the stumps. The crease is essential for ensuring that the bowler does not overstep while delivering the ball, which would result in a no-ball. When the bowler delivers the ball, their front foot must remain behind the bowler's crease. If the foot crosses the line, the delivery is considered illegal, and the batting team is awarded an extra run. This rule helps maintain fairness in the game of cricket.