Signing A PDF Document in Adobe Reader

In order to sign a PDF document in Adobe Reader, you must first create a Digital ID Certificate to use as a signature. Instructions to create a Digital ID is located here: Creating a Digital ID 

Open the document that needs a signature.  

Click the "All tools" tab along the top and then the "View more" link at the bottom. 

From the expanded menu, select the "Use a certificate" option

From the "Use a certificate" menu options, select "Digitally sign"

It will instruct you on how to add the signature to the document by clicking and dragging to the area you want to add the signature.

Once you have selected the area for the signature, it will prompt for you to select a Digital ID to use for the signature from any existing IDs.  Select the appropriate one and click Continue; otherwise select "Configure New Digital ID" to create a new one.  If prompted, enter the previously configured Digital ID password and click Sign.  

Adobe will then prompt for a location to save the newly signed document.  Click Save in the appropriate location and you have a signed PDF.