Introduction

Email message headers could provide a list of needed technical details about  messages exchanged, such as who sent it, the software used to compose it, and the email servers that it passed through on its way to the recipient.
Such information are need it in order to troubleshooting a variety of issues. 

This article  applies to: Outlook 2016, Outlook 2013, Outlook 2010, Outlook 2007.

In Outlook 2016, 2013, or 2010

1. In an open email message, click the File tab.

2. On the Info tab, click Properties.

   Header information appears in the Internet headers box.

In Outlook 2007

1. Open an email message.

2. On the Message tab, in the Options group, click the Dialog Box Launcher .

   In the Message Options dialog box, the headers appear in the Internet headers box.