Technology has advanced to the point that it is now possible to digitally sign a PDF document, here's the multiple ways on how to do it.

You can digitally sign a PDF when you don't have access to a printer or scanner, saving time and money. courtneyk/Getty Images ...

If you would like to learn how to digitally sign a PDF documents online for free using the cloud-based eSign PDF signature service this guide ...

Digitally Sign PDF Documents on Mac OS X Lion with Preview The revamped Preview app in Mac OS X Lion includes the extremely useful Digital Signature feature built right in.