Is SMTP still used?

SMTP or Simple Mail Transfer Protocol is mostly used for sending out email from an email client (e.g. Microsoft Outlook, Thunderbird or Apple Mail) to an email server. ... But in reality, it's still being used by several mail service providers.

Why was SMTP created?

Initially, SMTP was created to only transfer messages (with the help of MTAs — mail transfer agents). ... They were required to control rewriting the original messages to fix formatting issues when sending messages outside the organization. The message submission standard first introduced authentication for email sending.