You can create a leader line from any point or feature in a drawing and control its appearance as you draw it. Leaders can be straight line segments or smooth spline curves. Leader color is controlled by the current dimension line color. Leader scale is controlled by the overall dimension scale set in the current dimension style. The type and size of arrowhead, if one is present, is controlled by the first arrowhead defined in the current dimension style.
Most of the time a small line known as a hook line, dogleg, or landing connects the annotation to the leader. Hook lines appear with paragraph text and feature control frames—framing lines or boxes that surround numbers, symbols, or text—or if the last leader line segment is at an angle greater than 15 degrees from horizontal. The hook line is the length of a single arrowhead.
You can use the object snap modes to specify the start point of a leader accurately. You can also connect both straight and spline leaders to each other using the Endpoint, Midpoint, Near, Perpendicular, and Apparent Intersection object snaps. The connecting leader snaps to the specified snap point on the nearest leader line segment.