The TCP/IP suite of protocols provides a flexible email system that's built on basic protocols, including Simple Mail Transfer Protocol (SMTP) for sending mail, and Post Office Protocol 3 (POP3) for receiving mail.
Alternatively, the Internet Message Access Protocol (IMAP) can be used for receiving mail, as it enables access to email from any device, anywhere.
With POP3, the email message is downloaded from the email service and stored on the requesting device and can only be accessed using the same device.