We are using a custom letter-head as a background image for pages, which requires some margin at least on the top and bottom. At the moment, there seems to be no way to change this. As a workaround we are adding an empty text element to the top of the page to push down the following content. it kind of works, but it needs constant adjustment if the content changes. It would be easier if margins would be natively supported. Btw, we are looking to switch from PandaDoc and they are generally handling things like this quite well.