The simple answer is to bookmark the first address and cross reference it
where you want it repeated, but such is the nature of bookmarks that this is
easier said than done. It is all too easy to wipe out the bookmark.

A better way would be to use an ask field to request the information and put
ref fields at both locations where you want the information placed.
Alternatively, you could use a Fillin field, bookmark that field and use a
REF field at the second location to recall that bookmark.

Better still would be to create a userform to collect and place the
information. http://word.mvps.org/FAQs/Userforms/CreateAUserForm.htm

Note that ask and fillin fields do not automatically update. You would need
to force an update. Code to do that can be found on my web site at.
http://www.gmayor.com/installing_macro.htm