A signature file is a short text file you create for use as a standard appendage at the end of your e-mail notes or Usenet messages. For example, you might include your full name, occupation or position, phone number, fax number, e-mail address, and the address of your Web site if you have one. Many people also include a favorite quote, company motto, or short personal statement.
Most e-mail and Usenet news facilities make it possible for you to either create the signature file as part of the application or to specify another file you've created with a word processor. Then, you tell the facility (usually in an "Options" menu) the name of your signature file and it automatically adds it to the note or message template it provides you.