The message header is composed of several sections. Some of the sections are informational only, while others are links that provide extra functionality. The sections are:
Date: The date the message was received by the system.
From: The sender of the message.
To: The recipient of the message.
Reply-to: The email address you should reply to.
Subject: The subject of the message.
Full Headers: A link, if clicked which will show all the header details. The default setting is a brief display.