You can find many examples of web design questionnaires via Google, so first question answered.
For the second question: see how it's done in different forms. A clickable pdf isn't the most user-friendly way to do it. If you want a pdf it's probably better to use an online form that can print the answers and questions into a pdf.
Ok, so it's for a quote. Assuming you are using WordPress, I guess you can use any form builder that support conditionnal: gravity form, nija form, wpform, pionet etc... you have lot of choices.