SMTP, which stands for Simple Mail Transfer Protocol, is the software that allows you to send e-mail messages from your email addresses. Without it, you won't be able to use e-mail applications or webmail. When you send an e-mail, 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 connects to the remote email server and trades information. In case the recipient mailbox is available, your server transmits the e-mail to the receiving POP/IMAP server and the latter delivers that email to the specific mailbox in which the recipient can get it. If you wish to be able to send emails, it is recommended to ensure that the hosting company provides the service with their plans. Even though you work with an online form that site visitors use to contact you, you'll still require an active SMTP server for your hosting account for the web form to operate.
