The Two Points Draft Angle command measures an angle defined by a line between two selected points and the X-, Y-, or Z-axis. (See also Working with Dimensions TO BE REMOVED - INCORPORATED ELSEWHERE.)
Once the markup label is displayed, you can use the Flip Axis command on the Markup context menu to change the direction of the X-, Y-, or Z-axis segment used to form the angle. Right-click the label and select Flip Axis from the context menu.