An email header is simply a snippet of code in an email. This snippet of code contains many things about the email you have received. Some of the information the snippet of code contains is the sender and the recipient. More importantly the it contains the email’s route to get to the inbox along with authentication details. Just to clarify, the email header always precedes the email body.
You may ask yourself why would I care about the email header in my received email. Well it is a good question as to what purpose email headers serve. They provide information about the sender and recipient. For instance, who sent you the email (sender) and of course you (recipient). Another thing the email header provides is preventing spam. For instance, analyzing the information you can decide whether it really was the sender sending the email or just a fake email address. Which takes us to our next point identifying the email route. For instance, if you know the sender is in the US, but analyzing the email route shows more through India, China, Pakistan, you can pretty much know that it is spam.
Most email services, and others frown upon spam associated with email. So in analyzing the email header you can copy the information and send to your email service to report spam. At that point and the more that people do this can lead to less spam from the email service.
Email Header From Outlook 2010 and 2013 (Windows Only)
You will want to Add Message Options to the Quick Access Toolbar, by selecting the little down arrow in the upper left corner and choosing "More Commands..."
Step Two - On popup window with following steps
Choose All Commands from the top drop down.
Scroll until you find Message Options... then select
Select Add in the middle of the console
Message Options... (should now show up as a chosen command)
You should now see the Message Options icon in your Quick Access Toolbar at the top left corner.
Select the email from which you wish to get the headers.
Then select the Message Options icon in the top left corner.
A box similar to the one below should appear
Copy the data in the Internet headers box by clicking within the box and hitting Ctrl+A to select all text then hit Ctrl+C to copy the highlighted text.
Ctrl+V the data into our Email Header Analyzer tool and click Analyze.