SMTP, which is an acronym for Simple Mail Transfer Protocol, is the software that allows you to send e-mails from your email addresses. Without this, you will not be able to employ email applications or webmail. After you send a message, your SMTP server connects to a DNS server to determine exactly where e-mails for the recipient domain are handled. Then, it creates a connection to the remote email server and exchanges details. In case the recipient mailbox is present, your server sends the e-mail to the receiving POP/IMAP server and the latter delivers that message to the precise mailbox in which the recipient can access it. If you want to be able to send emails, it is recommended to make sure that the hosting company offers the service with their packages. Even though you use an online form that website visitors use to contact you, you still require an active SMTP server for your hosting account for the form to work.