Forum Moderators: mack
User agent behavior for a value other than an HTTP URI is undefined
The only reliable mechanism for processing a form submission is server-side technology meaning that if you want to send any form data to an email address you should use a server-side program that processes the form submission and sends the data to the email address.
Forms are most often created in HTML as everybody's web browser can open an HTML document. In order for your end users to open a PDF document they must have PDF viewer software installed. And if I remember correctly, there are certain stipulations for your end users if you are using advanced feature sets in Adobe Acrobat to create form documents. I believe they must actually have a full version of Adobe Acrobat installed, but I'm drawing from memory and conclusions on a project from quite a few years back now, so take that with a grain of salt.
Your best bet to have a form that works correctly is going to be simple HTML and a server-side form processing feature that will do with the form data what you will.