The size of the header/footer is determined by three factors:
1. The header/footer margin, which determines where the header/footer
begins.
2. The top/bottom margin, which determines where the space allotted for the
header/footer ends.
3. The actual depth of the header/footer.
The default Word Blank Document has the header and footer margins set at
0.5" and the top and bottom margins set at 1.0". This means that the top of
the header and the bottom of the footer will be half an inch from the edge
of the page. The top and bottom of the document (assuming it fills the page)
will be one inch from the edge of the page. The space between the header and
the top/footer and the bottom will depend on the depth of the header/footer.
If the header/footer exceeds the allotted space, it will push the document
body down/up but it will not change the actual margin setting. You can take
advantage of this fact to have, for example, a First Page Header that pushes
the top of the document down to accommodate a deep letterhead while the
Header that begins on page 2 will still be only one line and so will not
affect the top margin. For more, see
http://home.earthlink.net/~wordfaqs/HeaderFooter.htm
