Emacs/emacs/Mail-Signature

From Get docs

32.5 Mail Signature

You can add a standard piece of text—your mail signature—to the end of every message. This signature may contain information such as your telephone number or your physical location. The variable message-signature determines how Emacs handles the mail signature.

The default value of message-signature is t; this means to look for your mail signature in the file ~/.signature. If this file exists, its contents are automatically inserted into the end of the mail buffer. You can change the signature file via the variable message-signature-file.

If you change message-signature to a string, that specifies the text of the signature directly.

If you change message-signature to nil, Emacs will not insert your mail signature automatically. You can insert your mail signature by typing C-c C-w (message-insert-signature) in the mail buffer. Emacs will look for your signature in the signature file.

If you use Mail mode rather than Message mode for composing your mail, the corresponding variables that determine how your signature is sent are mail-signature and mail-signature-file instead.

By convention, a mail signature should be marked by a line whose contents are ‘-- ’. If your signature lacks this prefix, it is added for you. The remainder of your signature should be no more than four lines.