View Bcc recipients of an email message
If you add a recipient's name to the blind carbon copy Bcc box in an email message, a copy of the message is sent to the recipient. The recipient's name isn’t visible to the other recipients of the message (names entered in the To or Cc boxes).
View all Bcc recipients of a message I received
The only person who can see the names of Bcc recipients of a message is the sender.
View all Bcc recipient of a message I sent
If you are the message sender, do the following:
Open the message that was sent. By default, sent messages are saved in the Sent Items folder. All recipients appear in the header section of the message.