How to BCC in Apple Mailby K.C. Winslow
A blind carbon copy of an email sends an email to a recipient but hides the recipient's address and the fact that a copy was sent from any other recipients of the email. Apple Mail, the email application included on Mac OS X computers, has the ability to Bcc messages, but the option is not plainly visible as it is in many other email applications.
Click the "New Message" icon or open an existing message in Mail.
Click the customization icon. It appears to the left of the "From" field. Select "Bcc Address Field."
Type the email address in the Bcc field. Type a comma between multiple addresses to separate them. Alternatively, click on the field, press the "Address" icon and click on addresses to add them.