SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that enables you to send out e-mails from your email addresses. Without this, you won't be able to employ email apps or webmail. When you send an e-mail, your SMTP server creates a connection to a DNS server to discover where the emails for the recipient domain are taken care of. Following that, it connects to the remote email server and exchanges details. In case the recipient mailbox is available, your server sends the email to the receiving POP/IMAP server and the latter brings that e-mail to the precise mailbox in which the recipient can see it. If you'd like to send e-mails, it is best to ensure that the hosting company has the service with their plans. Even though you use an online form that website visitors use to get hold of you, you'll still require an active SMTP server for your hosting account for the form to work.