Hi Taha,
Use Mail Merge in MS Word with Excel as
the database. See
http://www.mvps.org/dmcritchie/excel/mailmerg.htm
Although this is for labels it works the same for letters.
Everything unique for each letter must be on the same
Excel row. A nice feature of filtered lists is that if you
use a filter only the filtered rows will be used.
Excel does not do letters by itself. If you do not have
MS Word then use John Walkenbach's
http://www.j-walk.com/ss/excel/tips/tip92.htm
but that would be only if you don't have Word.
Well I saw "Mail Merge" on the subject line, which was
not included in the question. If this is for email then you
would want to look at Ron's pages, and he was assuming email
Generally the routines would use your email application, so don't
know why he asked before giving offering a suggestion.
http://www.rondebruin.nl/mail/add-in.htm
http://www.rondebruin.nl/sendmail.htm