how to locate a footer in the bottom margin

in libo writer 5.0 I observe that a footer is allocated space from the text area and is not printed (as documented) in the bottom margin. How can I locate the footer line in the page margin area without reducing the text area? How can I assign the footer a position relative to the page?
Is writer in error or is documentation wrong?
I prefer a footer to be in the margin area, otherwise I would have to assign a different page format on (title) pages without footer…