SMTP commands are a set of rules that enable email clients to connect with email servers to initiate and manage message delivery, similar to how postal mail requires sender information, recipient information, postage, and other details. SMTP commands are used by email developers, IT professionals, system administrators, network engineers, and email marketers to send emails, manage email servers, and troubleshoot issues with delivery. Common SMTP commands include HELO, EHLO, AUTH, MAIL FROM, RCPT TO, DATA, BDAT, QUIT, and HELP, which serve various purposes such as initiating contact with a server, authenticating clients, confirming sender identity, and requesting permission to transfer data. While not necessary for basic email sending, knowledge of SMTP commands is essential for roles that interact with email servers and campaigns. Understanding SMTP commands can help streamline email marketing efforts and improve deliverability rates.