SIG - Signature File is one of the best small text files that you can use for your own benefit. It will also be able to get attached right to email messages and consists of the sender’s name as well as their email address. These email addresses may also consist of the signature of the recipient. The person’s title, and contact phone numbers will and should be included as well. There are also programs that support more than one signature file. You can use this extension to select what you need to within the create new message window. It is very easy to use.