Pick someone to send the message to and type that person's address at the prompt. Type a comma, and then put your username next in the field. This means the message will be sent to the person you chose and to you. The people who receive your messages can get a quick idea about your messages from the subjects. It's a good idea to spend a moment and think of descriptive subjects.
Messages have two parts.
Now you can type the body. Press CTRL-D to end the body. Some text may be displayed while your mail is sent. In nmh version 0.27 and above, you can simply type delete . The Example below shows what all that should look like.