Emails sent from Windows Mail don't contain contact information by default, except your name and the email address from which you send the message, and any information you chose to manually add to the end of your note to a sender. But Windows Mail supports an "email signature" feature that lets you store multiple signatures, like digital business cards to pick from when sending emails; you can even assign a different signature for each email account you have setup. The content of the "default signature" is automatically inserted, sparing you lots of keystrokes over time! Since signatures are just regular text inside the body of your message, you can just erase them when not needed. Windows Mail also lets you choose if your signature should be added to all outgoing messages, or only new ones (thus excluding email replies and forwards).
Side info: the email signature doesn't technically need to contain your contact information; any text will do. We've seen people integrated "Thanks," to the beginning of their signature, saving them some typing (but also weird looking when they forgot to erase that part, and seem to be thanking you for no reason!)
This is what you need to do to add your own signature to emails in Windows Mail:
Note: the signature setting only affects this copy if Windows Mail; if you use your email account from other email programs or webmail clients, you'll need to setup a signature for these as well.
Tip: create an email signature in...Test your signature: back in Windows Mail, click on the Create Mail button (or press Ctrl+N) to compose a message: your new signature was automatically added to the email body!
Tip: if you have multiple signatures, click on the Insert menu while composing a new message, and choose Signature to pick from another of your the signatures - it will add that signature where there was none, or replace the one that was already there.
You can associate one signature with a particular email account as follows: go to Tools > Options, and select the "Signatures" tab; click on a signature, and press the "Advanced" button next to the text box containing the signature text. Check / uncheck the email accounts you want to assign, and click OK to save; click OK once more to return to Windows Mail.
To delete a signature, go back to Tools > Options, and click on the "Signatures" tab. Select with a click the signature you no longer need, and click "Remove". If any email account was associated with that particular signature, they will start using the default instead; if the deleted signature was the default, the first one in the listing automatically becomes the new default. Caution: you will *not* get a confirmation message before Windows Mail deletes the signature, and the deletion cannot be undone (clicking Cancel will not do the trick!)