Sharing a PDF with 4 technicians in the document cloud

I am sharing a document with 4 technicians in the document cloud. I would like that document to stay untouched when they have to edit it in the field and send it to me via email. The problem I am having is any time a change is made to that PDF on our IPads it changes the document in the cloud--it also changes the PDF if we download it and store to the IPad. This PDF has a lot of fields to change for every customer that we service so deleting all that information every time will be time consuming. How do I change this behaviour? We were using a product called GoFormz that would allow us to edit and save/send but we always had access to the original untouched PDF