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 it, you will not be able to employ e-mail applications or webmail. Whenever you send an email, your SMTP server creates a connection to a DNS server to discover exactly where e-mails for the recipient domain name are managed. Then, it connects to the remote mail server and trades information. When the recipient mailbox is present, your server sends the e-mail to the receiving POP/IMAP server and the latter delivers that e-mail to the specific mailbox in which the recipient can get it. If you would like to send e-mails, it is best to ensure that the website hosting company provides the service with their plans. Even though you use an online form that website visitors use to make contact with you, you will still need an active SMTP server for your hosting account for the web form to operate.