| Header | Purpose |
| To: | Address of primary recipient(s) |
| Cc: | Secondary Recipients addresses |
| Bcc: | Blind Carbon Copies |
| From: | Person Creating the Message |
| Sender: | E-mail address of actual sender |
| Return-Path: | Path back to sender |
| Date: | Date and Time of Message |
| Subject: | One line summary |
| Reply-To: | Where replies should go |
| Message-Id: | Unique number for future referencing |
| Received: | Line added by each intermediate MTA |