There are many ways of inserting lines in PowerPoint. The easiest way is to
display the drawing tool bar. First you go to the view drop menu, and then
tool bars. You select the drawing tool bar and it will show the tool bar at
the bottom of the page. This tool bar has many drawing that you can insert
in your PowerPoint. For example you can make arrows, straight lines, curve
lines, shapes, etc,. You can also change the thickness and the colors of the
lines or of any drawing you make. Another way of insert a line is that you
may have your own line you want to insert; you can save the picture of your
line as a JPEG or as GIF file, and then insert the picture on your first
slide. If you want the line appear in all slides you just copy and paste
your graphic or picture on each slide.