Can I attach a pdf to a jotform as an appendix?

If you are looking to display a PDF file in your form, you can use the PDF embedder widget: https://widgets.jotform.com/widget/pdf_embedder 

https://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form 

If you want to attach a PDF file in the email notification(autoresponder) that is sent to the person who fills your form, you will find the "Add attachment" button in the ADVANCED settings:

Open a new thread if you need anything else, we will be glad to assist you.