User can download the “Pro-Forma” document from “My Account -> Orders” page, only if “Enable pro-forma” field of settings dashboard is active.
The pro forma invoice will be automatically generated by the system and it is not an official document. So, the button for creating a pro forma invoice will be visible only in front end for your customers in order to avoid any possible confusion with docuemtn managing for the administrator.
Following you find an example of pro forma invoice. It differs from a normal invoice for not having an invoice number and for the text “Pro forma Invoice” on top of the document.