???

Are you talking about editing a regular Word document, or using Word as
Outlook's default email editor? And what's an "email signature"?

If you are using Outlook and this is for one user only then you could
write an add-in in Outlook to add a signature to each message.   If you
are using Exchange and you want to do this for the whole company then
you'll have to do some coding on the Exchange server.

Sadly you didn't supply enough information to give us an idea of what you
want.  

Or do you want something which puts a signature in your Word eMail editor?
If so, perhaps may I suggest some form of AutoText?

- Malc
 www.dragondrop.com