LINE TOOL IN AUTOCAD

You will see the Line tool in the draw menu in the HOME screen.

or you can press L enter.
First specify the first point in the sheet. then use your mouse to give the direction and enter the dimension of the line.

  To draw a straight line you have to first click on the ORTHO MODE option. It is located at the bottom of the sheet. or simply press F8.

To end Line Command press enter or esc button.

Specify first point 

Sets the starting point for the line. Click a point location. With object snaps or grid snap turned on, the points will be placed precisely. You can also enter coordinates. If instead, you press Enter at the prompt, a new line starts from the endpoint of the most recently created line, polyline, or arc. If the most recently created object is an arc, its endpoint defines the starting point of the line. The line is tangent to the arc. 

Specify next point 

Specifies the endpoint of the line segment. You can also use polar and object snap tracking together with direct distance entry.