Updated: 04/02/2019 by Computer Hope

Short for electronic mail, e-mail or email is information stored on a computer that is exchanged between two users over telecommunications. More plainly, e-mail is a message that may contain text, files, images, or other attachments sent through a network to a specified individual or group of individuals.

The first e-mail was sent by Ray Tomlinson in 1971. Tomlinson sent the e-mail to himself as a test e-mail message, containing the text "something like QWERTYUIOP." However, despite sending the e-mail to himself, the e-mail message was still transmitted through ARPANET.

By 1996, more electronic mail was being sent than postal mail.

E-mail address breakdown

[email protected]
  • The first portion of all e-mail addresses, the part before the @ symbol, contains the alias, user, group, or department of a company. In our above example, support is the Technical Support department at Computer Hope.
  • Next, the @ (at sign) is used as a divider in the e-mail address; it is required for all SMTP e-mail addresses since the first message was sent by Ray Tomlinson.
  • Finally, computerhope.com is the domain name to which the user belongs.

How to send and receive e-mail

E-mail program

To send and receive e-mail messages, you can use an e-mail program, also known as an e-mail client, such as Microsoft Outlook or Mozilla Thunderbird. When using an e-mail client, you must have a server that stores and delivers your messages, hosted by your ISP or in some cases, another company. An e-mail client needs to connect to a server to download new e-mail, whereas e-mail stored online is always available, from any of your devices connected to the Internet. For more information about cloud e-mail service, see the difference between webmail and an e-mail client, below.

Online e-mail

An alternative way of sending and receiving e-mail (and the more popular solution for most people) is an online e-mail service or webmail. Examples include Hotmail (now Outlook.com), Gmail, and Yahoo Mail. Many of the online e-mail services, including the ones we mentioned, are free or have a free account option.


An e-mail service will not provide you with an Internet connection. You'll still need to use an ISP to connect to the Internet to use the e-mail service.

Writing an e-mail

When writing an e-mail message, it should look something like the example window below. As you can see, several fields are required when sending an e-mail:

  • The To field is where you type the e-mail address of the person who is the recipient of your message.
  • The From field should contain your e-mail address.
  • If you are replying to a message, the To: and From: fields are automatically filled out. If it's a new message, you'll need to specify the recipients in the To: field, either by selecting them from your contact list, or manually typing the full email addresses. If you are manually specify more than one recipient (as in a group e-mail), the addresses should be separated by a comma and a space, or by pressing the Tab key.
  • The Subject should consist of a few words describing the e-mail's contents. The Subject lets the recipient see what the e-mail is about, without opening and reading the full e-mail. This field is optional.
  • The CC ("Carbon Copy") field allows you to specify recipients who are not direct addressees (listed in the "To" field). For instance, you can address an e-mail to Jeff and CC Linda and Steven. Although the e-mail is addressed to Jeff, Linda and Steven will also receive a copy of the message, and their addresses will be visible to Jeff, and to each other. This field is optional.
  • The BCC ("blind carbon copy") field is similar to CC, except the recipients are secret. Each BCC recipient will receive the e-mail, but will not see who else received a copy. The addressees (anyone listed in the "To" field) remain visible to all recipients. This field is optional.
  • Finally, the Message Body is the location you type your main message. It often contains your signature at the bottom; similar to a handwritten letter.

Writing an e-mail message

What makes a valid e-mail address?

There are several rules that an e-mail address must follow to be valid:

  • As mentioned earlier, an e-mail must have a username followed by @ (the at sign) which is followed by the domain name with a domain suffix.
  • The username cannot be longer than 64 characters long, and the domain name cannot be longer than 254 characters.
  • There should be only one @ sign in an e-mail address.
  • The space and special characters: ( ) , : ; < > \ [ ] are allowed. Occasionally, a space, backslash, and quotation mark work but must be preceded with a forward slash. Although valid, some e-mail providers do not allow these characters.
  • The username and e-mail addresses as a whole cannot begin or end with a period.
  • The e-mail must not have two or more consecutive periods.

Advantages of e-mail

There are many advantages of e-mail and the usage of e-mail versus postal mail. Some of the main advantages are listed below.

  • Free delivery - Sending an e-mail is virtually free, outside the cost of Internet service. There is no need to buy a postage stamp to send a letter.
  • Global delivery - E-mail can be sent to nearly anywhere around the world, to any country.
  • Instant delivery - An e-mail can be instantly sent and received by the recipient over the Internet.
  • File attachment - An e-mail can include one or more file attachments, allowing a person to send documents, pictures, or other files with an e-mail.
  • Long-term storage - E-mails are stored electronically, which allows for storage and archival over long periods of time.
  • Environmentally friendly - Sending an e-mail does not require paper (paperless), cardboard, or packing tape, conserving paper resources.

What's the difference between webmail and an e-mail client?

Both webmail and an e-mail client perform the same function: they allow the user to send and receive e-mail. However, an e-mail client requires the user to install software directly onto their computer; if the software is not installed, e-mail may not be accessed. Also, many e-mail clients cost money, but are generally more secure. Webmail, on the other hand, is a free service, hosted in the cloud. The cloud service will automatically synchronize your e-mail to all your devices, including your desktop computer, tablet, or smartphone.

There are many e-mail clients (those that are software-based, not online) available for users today. The following list contains some of the most popular clients, and some of these are free to use.

What can be sent in an e-mail?

In addition to text messages being sent over e-mail, it is also possible to attach a file or other data in an e-mail. For example, an attachment could be a picture, PDF, word processor document, movie, program, or any file stored on your computer. However, because of some security issues, it may not be possible to send certain types of files without additional steps. For example, many companies will block .exe files from being sent over e-mail and would require you to compress the file into a .zip file. Also, most e-mail providers have file size restrictions that would prevent any large files or programs from being sent over e-mail.

Should I use "e-mail" or "email" in my writing?

Both "e-mail" and "email" are valid words and what you decide to use should be determined by the style guide you're following. Computer Hope chooses to use a hyphen in "e-mail" because it is a compound noun that is made of the words "electronic" and "mail."

Attachment, Business terms, Computer abbreviations, E-mail terms, Internet terms, Network terms, Signature, SMTP, Snail mail, Spam