How email works

Email (i.e. electronic mail) may be the most heavily used feature on the Internet. You can use it to send messages to anyone who is directly or indirectly connected to the Internet.

How email is delivered over the Internet

Just like most other Internet data, emails travel as a stream of packets using the Internet's TCP/IP protocol. Just a quick recap:

1. The TCP protocol breaks the email into packets, each bearing the addresses of the sender and the recipient.
2. The IP protocol delivers the packets to the right destination. Routers on the Internet examine the addresses in each packet, calculate the most efficient path to the email's destination server, and forward the packets to the next router. Many factors go into how the packets are routed, including traffic volume on the networks. 
3. When the packets have arrived, TCP recombines them into an email that the recipient can read.

How email software works

At a minimum, email software lets you send people emails and read emails that people have sent you.

• Checking your email. When someone emails you, the message gets sent to a mail server, not straight to your computer. Your email software logs in to the mail server and checks to see whether you have mail. If you do, you'll see a list of your new mail messages, including the sender's name, the email's subject, and the date and time the email was sent.
• Reading your email. If you want to read an email, you tell your software to download it, and you read it in your email program. Emails normally consist of webpages fully formatted in HTML. You can embed links in your emails, such that your addressees can open the linked pages in their browser with a single click or tap.
• Handling your email. Email software lets you delete, forward, or reply to your emails. If you aren't ready to respond right away, you can create folders in your email software for storing mail. You can also keep track of people's contact information and search through your saved emails at any time.