I don't know what that means. I think you are making a Path with the Pen tool, not a line. The Path needs to be stroked in order for it to "be" there.
Use the Line tool. You can turn off the arrowheads in the Options Bar. See the little black triangle?
Having said that, Photoshop is not the right program to make a letterhead. Illustrator or Freehand would be more appropriate because they produce vector graphics which are more scalable..
I am creating a company letterhead in Adobe Photoshop.
I almost finished it all and all what's left is to draw a horizontal line under the text and that's where I get the problem. The Line tool would give me the arrow instead of the straight line. I was finally able to draw the line with the Pen tool, but that line is black, instead of navy, as the rest of the letterhead. Also, I can't make this line seeker.