To really understand what an email header is, you must see one. Here is an example of a full email header:

Return-Path: <>
X-SpamCatcher-Score: 1 [X]
Received: from [] (HELO
by (CommuniGate Pro SMTP 4.1.8)
with ESMTP-TLS id 61258719 for; Mon, 23 Aug 2004 11:40:10 -0400
Message-ID: <>
Date: Mon, 23 Aug 2005 11:40:36 -0400
From: Taylor Evans <>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: Jon Smith <>
Subject: Business Development Meeting
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

Email headers should always be read from bottom to top.

Below are some header characteristics:

From: sender's name and email address (IP address here also, but hidden)
To: recipient's name and email address
Date: sent date/time of the email
Subject: whatever text the sender entered in the Subject heading before sending

For more information please follow this LINK