SMTP, which stands for Simple Mail Transfer Protocol, is the software that enables you to send messages from your email addresses. Without it, you won't be able to employ e-mail apps or webmail. When you send an e-mail, your SMTP server creates a connection to a DNS server to learn where the emails for the recipient domain name are managed. Following that, it connects to the remote mail server and exchanges information. When the recipient mailbox is present, your server sends the message to the receiving POP/IMAP server and the latter brings that e-mail to the specific mailbox where the recipient can access it. If you want to be able to send e-mails, it is best to make sure that the hosting company has the service with their packages. Even though you work with an online form that website visitors use to get hold of you, you will still need an active SMTP server for your hosting account for the form to operate.