The Includes line is drawn between Use Cases on a Use Case diagram. An Includes relationship means that a Use Case includes the behavior described in another Use Case. The relationship is drawn from the base Use Case to the included Use Case (so that the arrowhead is attached to the included Use Case end). Semantically, the relationship means that the behavior of the included Use Case is inserted into the behavior of the base Use Case.
The Includes relationship is a vector with a dashed line that has a <<includes>> stereotype notation added to it. You may optionally name the line; in either case, the <<includes>> stereotype is automatically added to the line after it is drawn.