What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I am not sure I am able to understand your question completely. So, please correct me if my response is not appropriate.
First off, I do not understand why you would want to open a JotForm form with a PDF reader.
This is your form http://www.jotform.com/2912123196 if you click on it, it should open in your browser
The form is a web based application, so, a browser is needed to use/open it.
But perhaps what you wanted to say is, you want adobe reader as the default PDF reader for your files (including JotForm PDF files and reports) in your Windows 8 system.
For that, I suggest you review this tutorial I found on the internet.
Please inform us if you need further assistance.