Headers include identifying information such as the routing information of the message: the sender, recipient, date, and subject. Some headers are mandatory, such as FROM, TO, and DATE. Others are optional, but commonly used, like SUBJECT and CC.
Other headers may include good time stamps for when the message was sent, and the recipient time of all mail transfer agents that are associated with the message's delivery. Whenever a message is sent, each server or service that touches it (the MTA or Mail Transfer Agent) will leave a stamp.
The headers precede the information sent in the body of the e-mail
Retrieve Headers in Outlook Express
1. Open the e-mail message in a new window, usually by double-clicking on it.
2. From the File menu, click "Properties."
3. Click the Details tab.
4. Click "Message Source." A new window will open containing all the headers and original message.
5. Right-click anywhere inside this window and click "Select All."
6. Right-click again and choose "Copy."
7. You can now close this window and the message window to return to Outlook Express. The header information can be pasted into an e-mail response for a support ticket, a text file, or a chat window so that Support can provide you with more information.