When you have a website hosting account and you set up an e-mail address, you may take the option to send out and receive emails for granted, but in fact, that isn't always true. Sending e-mails isn't always a part of the website hosting plans that companies offer and an SMTP service is needed to be capable to do that. The acronym represents Simple Mail Transfer Protocol and this is the piece of software that allows you to send emails. If you use an email app, it connects to the SMTP server. The latter then requests the DNS data of the domain, which is a part of the receiving address to find out what mail server manages its emails. After some system information is interchanged, your SMTP server provides the message to the remote IMAP or POP server and then the e-mail is finally delivered in the corresponding mailbox. An SMTP server is required if you use some sort of contact form as well, so in case you work with a cost-free hosting plan, for example, it is very likely that you will not be able to make use of this type of form as many cost-free web hosting companies do not allow outgoing email messages.