The initials Bcc, for "Invisible Carbon Copy", are part of a set of sending options that are offered to you when you send an email. Perhaps you are usually paying attention only to the recipient field, "To", or its fake twin, "Cc" (carbon copy)? However, the "Bcc" can be very useful.
Have you already sent or received a group mail addressed to several recipients? In both cases, when you view your mail history received or sent, all the people affected by the message are displayed. It is precisely to avoid this that the "Cic" exists. By sending your mail to people in the Bcc field, they can not see all the recipients. In other words, it's a way to send a bulk mail without the recipients knowing that your message is being sent to a group of people. How is it useful? If for example you are organizing a party with guests who do not know each other or if you do not want them to see your list of guests. In one mail, your invitation will be gone. Each recipient will answer you, without the others being informed.
How to proceed in practice? If you want none of your correspondents to see the other recipients of the email, place all your contacts in the Bcc field and put your email in the recipient field. Thus, when your correspondents receive your message, they will each have the illusion of being the only recipient. You can not customize the message for each recipient, of course.
The sending of mail with a recipient in "Bcc" is very used in the professional environment. It allows for example to send a mail to a client, while placing a copy of a manager, a colleague without revealing his email address.