Recipient / To

Here you enter the email address of the recipient

If you click the icon (shown circled in red above) you can choose a recipient from your contacts (people) list

You can click "Cc & Bcc" if you wish to send to multiple recipients

The CC box can be used to send a copy to other recipients where all recipients can see who it has been sent too whereas BCC hides additional recipients (which is what you should use if sending to multiple recipients)

Subject

Here you enter the subject (title) of your email message, it is advisable not to leave this blank as many email systems will treat it as junk mail (spam)

Message

Here you type the main body of your email message

Format Toolbar

Change font size, style, colour and paragraph settings for your message

Insert Toolbar

Attach a file to your email, or insert a photo, table or link to a website

Send

When you have finished composing your email message click this button to send it