Finding BCC in Internet mail headers

There is no such thing as a "BCC field"; BCC in email is performed by adding the recipient to the envelope but not the headers, which means that they are undetectable unless the email server is explicitly configured to reveal them somehow.

In the internet headers, you should see a line Received by: xyz for <your email addr>.

Here is the simple test case I have created for the BCC field.

1. Create new email with BCC only.

   

2. Check the raw message at received end(Here I sent to Gmail). If you have a close look on the raw message in the screen shot with highlighted for then you can see the BCC which I have added while sending an email.