Is it possible to insert fields into the body of an e-mail that would
automatically display the contents of the "To" and the "Subject"
fields?
Not out of the box, but I don't see why you couldn't write a little code
to do it, should be easy enough, just to have Outlook check for a certain
string within an email message when sending and, if present, replace it with
the data you want to replace it with, but, one has to ask, why? I've yet
to see a mail client that doesn't display the subject and the To field, why
do you need them added to the body of the message as well?