One, Word generally recalls the previous Window configuration - create a new Blank Document, configure it the way and in the location you prefer, then Close the Window - your next Blank Document *should* resemble the previous document.
Two. Option-Click on the Green Button; "Click" generally leads to a Full Screen Window, and Option-Click executes the Window>Zoom Command. Three, execute the Window>Zoom Command from your Mac's Menu Bar. In either of these two instances, I recommend closing that new Blank Document, with the same rationale - Word should recall the last Window configuration of the New Blank Document you created and closed.