Hello!
I want that the user download a PDF document. I have found a lot of information about how the user can upload a document, but I want the user found the document and just download it.
I really need it.
Thanks 
I suppose it’s an uploaded PDF file (if not there it’s just a plain link to the PDF file).
Add a container in your UI designer form. Set collection to your context document ref (I have a multiple document scenario). Inside the container add a link with text {{ $item.fileName }} and URL to “/bonita/portal/” + $item.url (expression)
This should do the trick!
Thank you a lot!! It works!!
Please consider accepting my answer then 
Sorry, Im new in this place, done! check it please!!