CCList is a TIdEMailAddressList property used to store the email address of recipients that will receive a carbon copy of the message. 

Use BccList to indicate recipients that will receive a carbon copy of the message, but do not appear in the "To:" headers for the original Recipients of the message.

(Delphi) Updating a list of CC:d email addresses 

  AMessage.CCList.EmailAddresses :=
  '"John Doe" <jdoe@some.net>, "Jane Doe" <janed@another.net>';

  // or....

  with AMessage.CCList.Add do
  begin
    Name := 'John Doe';
    Address := 'jdoe@some.net';
  end;

  with AMessage.CCList.Add do
  begin
    Name := 'Jane Doe';
    Address := 'janed@another.net';
  end;

TIdEMailAddressList 

TIdEMailAddressItem 

TIdMessage.BccList 

TIdMessage.Recipients