PDF Signing Solution

Clients want simple solutions; moreover many are not IT lovers and just want things to work. We send out a lot of PDF’s that need signing. EchoSign far too complicated. Most clients will be running Acrobat reader on a PC or hand held device. What is the best and easiest method to embed an ability for a recipient of a PDF using Reader to sign? If you start using JavaScript popups etc then they often do not function on mobile devices. Is there are way of embedding something that will allow the recipient to see that they have been asked to sign and when they click to sign it confirms they have accepted the document which they can then email back?