Go to the Insert Tab. In the Illustrations group click on Shapes. There you will find a Line tool.

I like to add into this turn on the ruler tool if not done already this will give you an idea of where the line may go based on the ruler.  keep in mind the space for your footer and header.

I have done all of these things, I was just wanting to get an exact 3 1/2 inches. The closest I have gotten with the ruler is 3 9/16 and 3 7/16 inches which will work. I was just wondering if there was an exact way to measure the placement. Thanks

Draw your line. Then on the Ribbon go to Position -- More layout options. Then in the Vertical section of the Layout Dialog for Absolute Position enter 3.5. Click OK and your line will be positioned where you want it.

Thank you Kevin I will try this

Am I missing something on my ribbon? I can't find Position on my Ribbon.

I have a Position under the layout tab but it is grayed out.

I figured it out Kevin, I was drawing my line wrong and it wasn't giving the options that I needed. I was just doing three hyphens and enter and is drew the ling from margin to margin. But I couldn't use the position options. I like your way better because I can draw the line from edge to edge.

If you place the cursor where you want to START the line, HOLD SHIFT key, then drag the line to where you want to end, this will give you a straight line even if your mouse strays "off line".  Then go to options and adjust size.

Another approach, if you send many of these, might be to look at a letter folding machine or paper creaser.  If your paper is folded consistently, you can adjust the report to the fold.  

Additionally, if you have access to a guillotine style paper shear, you could line your paper up at the 3.5" mark on the ruler and run your thumb down the stationary blade for a quick and accurate crease.