To center table vertically and horizontally to the middle of page in Word, you need:Click with right mouse button on table
, to show the options and select Table Properties
In Table Properties window, set Text wrapping
and then click on Positioning
In Table Positioning window, set both Horizontal and Vertical position
and Relative to Page
To have your table aligned exactly to the middle, check if there are correct values in the Distance to surrounding text
and also in Before and After spacing.