Hi Brad Qualls,
Could you please let us know the adobe application you are using and also the OS version on your system?
To digitally sign a document you need to select the certificates option from Tools.
You can navigate to tools pane and type " Certificates" in the search box. And then select "digital sign" option .
Let us know if this helps.
I am running OS X Yosemite 10.10.2. Adobe Acrobat Pro DC 2015 Release ver 2015.006.30121.
Thank you Sarojini,
I was missing the Certificate button on the right side of the screen. I usually just paste my signature in from a png file and fill in the rest of the information with text. I was able to create a digital signature and add the appropriate png.