Updated: 12/10/2023 by Computer Hope
Digital envelope representing an e-mail alert.

Short for electronic mail, e-mail or email is information stored on a computer that is exchanged between two users over telecommunications. More plainly, an 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 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 sent than postal mail.


E-mail was featured as a top term of 1997.

E-mail address overview

Breakdown of an e-mail address

  • 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 a divider in the e-mail address; it's required for all SMTP e-mail addresses since Ray Tomlinson sent the first message.
  • Finally, "computerhope.com" is the domain name where the user belongs. The ".com" is the TLD (top-level domain) for our domain. The domain name is used to route the email to the correct destination server.

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, a server that stores and delivers your messages is used. This server is often hosted by your ISP but can be another Internet company. An e-mail client needs to connect to a server to download new e-mail, whereas e-mail stored online is always available to any Internet-connected device. 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 online e-mail services, including the ones we mentioned, are free or have a free account option.


An e-mail provider doesn't provide an Internet connection. You'll still need 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 the e-mail address of the person receiving the e-mail is placed.
  • The From field should contain your e-mail address.
  • If you reply to a message, the To: and From: fields are automatically filled out. If it's a new message, you must have one recipient in the To: field by selecting them from your contact list or typing the e-mail addresses. If you enter multiple recipients (e.g., group e-mail), the addresses should be separated by a comma and a space or by pressing the Tab.
  • 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 lets you 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 also receive a copy, and everyone can see who received the e-mail. This field is optional.
  • The BCC (blind carbon copy) field is similar to CC, except the recipients are secret. Each BCC recipient receives the e-mail but does 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?

The following rules make an e-mail address valid:

  • As mentioned earlier, an e-mail must have a username followed by @ (the at sign), and a domain name with a domain suffix.
  • The username cannot exceed 64 characters long, and the domain name cannot exceed 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 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 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 nearly anywhere worldwide, 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 users to access them far in the future.
  • Environmentally friendly - Sending an e-mail does not require paper (paperless), cardboard, or packing tape, conserving paper resources.

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

Both webmail and an e-mail client perform the same function: they allow users 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 automatically synchronizes your e-mail to all your devices, including your desktop computer, tablet, or smartphone.

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

What can be sent in an e-mail?

In addition to sending text messages, e-mail can also have attachments. 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, sending certain types of files may not be possible without additional steps. For example, many companies 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 prevent large files or programs from being sent over e-mail.

What is e-mail format?

When signing up for a newsletter or other e-mail service, you may be asked to choose your preferred e-mail format. The e-mail format is usually "Text" or "HTML." This format means the e-mails are either text (plaintext) with no formatting or images or HTML (hypertext markup language), which resemble what you see in your browser.

These options are offered because not all e-mail clients can properly format e-mails sent as HTML and because some people don't use anything more than text in their e-mails.


If you're unsure what option to choose, select HTML (with pictures) since most e-mail clients can display these e-mails without problems. If you encounter problems, you can change your settings or unsubscribe and then resubscribe with the text option.

How to send Computer Hope an e-mail

See our contact page for ways to contact Computer Hope through e-mail and other forms of communication.

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's a compound noun made of the words "electronic" and "mail."

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