SMTP, which is short for Simple Mail Transfer Protocol, is the software that enables you to send emails from your email addresses. Without this, you will not be able to employ email applications or webmail. Every time you send an email, your SMTP server connects to a DNS server to discover where the e-mails for the recipient domain name are managed. Then, it connects to the remote email server and exchanges information. In case the recipient mail box exists, your server transmits the e-mail to the receiving POP/IMAP server and the latter delivers that e-mail to the particular mailbox in which the recipient can access it. If you wish to send e-mails, it is best to make sure that the website hosting company offers the service with their packages. Even though you work with 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 form to function.