In case you have a shared hosting package and you create an e-mail address, you may consider the option to send and receive emails for granted, but in fact, that isn't always true. Sending email messages is not always a part of the web hosting packages that service providers feature and an SMTP service is necessary to be capable to do that. The acronym stands for Simple Mail Transfer Protocol and that is the piece of software that enables you to send e-mails. If you are using an e-mail app, it connects to the SMTP server. The latter then searches the DNS records of the domain, which is a part of the receiving address to find out what email server manages its emails. After some system data is swapped, your SMTP server delivers the message to the remote IMAP or POP server and the e-mail is finally delivered in the related mailbox. An SMTP server is necessary if you work with some sort of contact page also, so if you have a free hosting plan, for example, it's probable that you will not be able to make use of such a form as most free of charge hosting providers do not allow outgoing e-mail messages.