SMTP, which is short for Simple Mail Transfer Protocol, is the software that allows you to send emails from your email addresses. Without it, you will not be able to employ e-mail apps or webmail. Whenever you send an email, your SMTP server connects to a DNS server to learn exactly where emails for the recipient domain name are handled. Then, it connects to the remote mail server and trades details. When the recipient mail box is present, your server sends the email to the receiving POP/IMAP server and the latter delivers that message to the precise mailbox in which the recipient can find it. If you'd like to send emails, you should always make certain that the website hosting company provides the service with their plans. Even though you use an online form that visitors use to contact you, you'll still require an active SMTP server for your hosting account for the web form to function.