How do I have a disclamer at the bottom of all my emails

Question

How do I have a disclamer at the bottom of all my emails, somthing like
"Please note: Under Florida law (Fla.Stat. 668.6076 - effec. 07-01-06), e-mail addresses are public records. If you do not want your e-mail address released in response to a public-records request, do not send electronic mail to this entity. Instead, contact this office by phone or in writing"

Answer 1

In preferences there is only one window that opens, thats accounts, of which I have 3, there in each I have three options, Account Information, Mailbox behavior, and advanced, there is nothing else. Done all u have suggested, there is no signatures.
How can you not have the other panes in Preferences?
If you're absolutely sure that the toolbar of the
Preferences window is not collapsed, then I would
suggest reinstalling or maybe looking at the Mail
application in another account.
BTW- The instructions from Mail Help on how to add a
signature:
1.Choose Mail > Preferences and click
Signatures.
2. If you have more than one email account, select
the account you want to create a signature for.
3.Click the Add button and enter a description
for the signature.
Mail creates a default signature for you.
4. Select any part of the default signature that you
don’t want to use and enter your own text.
5. Select “Always match my default message font” or
use the Format menu to change the font, color, style,
and alignment of your signature text.
When you add formatting, your signature becomes rich
text. You can also drag a picture or a vCard file to
your signature.
6. Use the Choose Signature pop-up menu to choose the
default signature for the account.
Choose None if you don’t want a signature to appear
automatically. To have Mail randomly select a
signature, choose In Random Order. To have Mail
insert each of your signatures in order, choose In
Sequential Order. To change the order, drag the
signatures in the list.
7. If you want your signatures to appear above the
quoted text in a reply, select "Place signature above
quoted text."
Otherwise, signatures appear below the quoted text.