I am in the process of creating a form but need to add a section to collect attendee's names, email address and volunteer roll.

I am not sure how to do this. It could be 2 to 10 or more names. I thought about a text box for the user to just type in the information, then I saw something about writeable PDF's. Can I just JotForm for part of the form and insert a Writeable PDF for other information or does it have to be one or the other?

Fillable PDF forms are PDF version of your web form:

http://www.jotform.com/help/312-Fillable-PDF-Everything-you-need-to-know-about-JotForm-Fillable-PDF-Creator

It is not possible to use both in conjunction.

For any sort of repeating sets of fields that have a variable number of entries, I would recommend using a configurable list widget:

http://widgets.jotform.com/widget/configurable_list

This will allow you to create a set of fields that will give the user the option to add more sets if required.