SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that allows you to send out messages from your email addresses. Without it, you will not be able to employ email apps or webmail. Once you send a message, your SMTP server connects to a DNS server to determine exactly where e-mails for the recipient domain name are taken care of. Then, it creates a connection to the remote mail server and exchanges details. When the recipient mail box is present, your server transmits the message to the receiving POP/IMAP server and the latter delivers that message to the particular mailbox in which the receiver can access it. If you want to be able to send emails, it is recommended to make certain that the web hosting company offers the service with their plans. Even though you use an online form that visitors use to get hold of you, you'll still need an active SMTP server for your hosting account for the form to function.