In email, CC stands for carbon copy, while BCC stand for blind carbon copy. Those email addresses listed under CC in an email get a copy of the email, and everyone on the list can see who they are. Those email addresses listed under BCC receive an email, but it is not visible to other recipients.
Carbon copy is typically used to allow others a chance to view the email even if you do not need them to reply or take action. If the receiver of the email who is listed under the “To” part hits reply, all the other email addresses in the CC will receive that reply.
If you want to show the email to people but keep the fact that they can see it hidden, BCC is the field to use. It’s useful to use BCC in situations where there’s a long mailing address or when the recipients don’t know each other and would rather keep their identities a secret. It’s also common to add people to BCC fields in the case of disciplinary action if the BCC recipient needs to know about the message but the sender doesn’t want to needlessly embarrass the main recipient.