Brenda, I think it depends on what version of Outlook you have, but I can tell you how it works with mine. I have Outlook 2000 and if you compose a new e-mail, the CC and BCC fields automatically appear underneath the TO: field.
If your BCC field is not showing up, go to the 'View' drop down menu and the BCC option can be checked and it will now appear automatically when you compose a new e-mail.
To familiarize myself with using the BCC field, when I sent a new e-mail to someone, I would BCC myself using an alternate e-mail account just to test try it out. If you go back and look at your original e-mail, you will note that it doesn't show anywhere you have also sent it to yourself (hence the 'blind' part of the BCC) and double-check that you did, in fact, receive the extra blind copy on your other e-mail account.
Hope that makes sense and doesn't just confuse you further, lol!