Can I link a PDF to my form?

Do you mean you want to have a PDF file on your form? If yes, then you can use the PDF Embedder widget for your form.

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

Here's a link to a demo so you can see it in action: http://form.jotformpro.com/form/51863020628957?

Here's how to add a widget to a form: How to Add a Widget to your Form

Do let us know if you need further assistance.