Would it be possible to add a link to a file on the form?

Can I put a link to a document in my form?  Can the document be a PDF?

To my understanding, you would like to add a link to your form that will redirect to a PDF file when accessed OR it will download a PDF file when clicked.

That would be possible. What you need to do is follow the instruction that is in this guide — How-to-Add-a-Downloadable-File-to-Your-Form

If you have any further question, please feel free to let us know.