The Line command on the Home tab 
Draw panel launches the AutoCAD LINE command. Use this command to draw a line by selecting start and end points.
To create a line by selecting a start and end point
- Click Home tabDraw panelLine drop-downCreate Line
.At the Command prompt, enter line. - Specify the start point.
You can use the pointing device or enter coordinate values on the command line.
- Complete the first line segment by specifying the endpoint.
To undo the previous line segment during the Line command, enter U or click Undo on the toolbar.
- Specify the endpoints of any additional line segments.
- Press Enter to end or C to close a series of line segments.
- To start a new line at the endpoint of the last line drawn, start the Line command again and press Enter at the Specify Start Point prompt.