It separates the user name from the domain name. To read and send mail, users need to access the computer where their mailbox resides. This computer is called the server. The server is the computer which stores, receives, and sends e-mail messages over the Internet. In addition to simple letters, memos, messages, etc., other types of files can be added to e-mail messages as attachments.
Attachments can be files such as a word processing document, a spreadsheet, or a graphic image.
That file can then be downloaded onto the recipient's computer. There are two basic ways. First, an e-mail message can be addressed to a group of people, such as the entire library staff, an entire department or division or an entire medical center. The e-mail is then sent to all of the addresses listed . The second method is called a mailing list or listserv.