What does BCC in an email do?

BCC stands for Blind Carbon Copy. Any address in that field will receive the email just like any in the To field. However, no one will see what addresses were included in that field as it is not displayed in the received email. Even those who receive it thanks to the BCC field will not see their email addresses listed: only the To field shows up in the recipient's email.

A common use for this field is to send an email both to a subordinate (in the To field) and to manager or personnel (in the BCC field) so that the folks in the BCC field are kept in the loop about the issue needing to be addressed and therefore has a "paper trail" regarding said issue but so that the subordinate does not feel put on the spot or threatened.

BCC in an emails stands for "blind carbon copy." Any email addresses you put in the BCC line will receive your email, but would not be able to see anyone else who also received your email.