using Envelope sender vs From:address

HI

I am deploying a SMG VM and need help with policy creation.

What is the difference between using:

If text in From/To/Cc/Bcc Address part of the message contains 1 or more occurrences of

and

Envelope sender/receiver.

Also 10.6 does not contain the bcc component. How can we use that?

Will using envelope sender cover the "from:" part and will using envelope receiver conver "to/cc/bcc" is my the query i have in specific.

Thanks.