Email may be the most complex internet thing.
Are you trying to send email within your own domain or over the internet? They are two different things, but, in any event, you need to configure a mail transfer agent (MTA) such as sendmail or postfix, a mail delivery agent (MDA) such as procmail, and a mail user agent (MUA) such as mutt or mail.
Do you want to run your own mail server or connect to a mail server on the internet, such as Gmail or you ISP's mail service? Note that many ISPs frown on users running public-facing email servers unless they have business-level accounts because of (what I consider) quite legitimate concerns about spam.
Here is an excellent tutorial
about setting up Mutt to send and receive your email via an external mail service. I did a podcast earlier this year about my own experiences in learning how to use Mutt
After a little research, you should be able to frame your question more precisely.
I think it would help for you to do a little research and determine what exactly you are trying to accomplish, as email is such a complex thing with so many variations.