SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that enables you to send out emails from your email addresses. Without this, you will not be able to employ e-mail applications or webmail. When you send an e-mail, your SMTP server creates a connection to a DNS server to find out exactly where e-mails for the recipient domain are managed. After that, it creates a connection to the remote mail server and exchanges details. If the recipient mailbox exists, your server transmits the e-mail to the receiving POP/IMAP server and the latter brings that message to the specific mailbox where the recipient can access it. If you'd like to be able to send emails, it is recommended to ensure that the website hosting company has the service with their plans. Even though you make use of online form that site visitors use to get hold of you, you'll still need an active SMTP server for your hosting account for the form to work.