You cannot add them to the letters produced by executing the merge and
unless you have a printer that can automatically handle the change between
feeding an envelope and feeding the paper for the letter, you would be
better off doing a separate envelope mail merge that uses the same data
source as was used for the letter.
--
Hope this helps.
Please reply to the newsgroup unless you wish to avail yourself of my
services on a paid consulting basis.
Doug Robbins - Word MVP, originally posted via msnews.microsoft.com