Software & Apps > MS Office How to See Full Email Headers in Outlook.com How to see more information in email headers in Outlook.com By Heinz Tschabitscher Heinz Tschabitscher Writer University of Vienna A former freelance contributor who has reviewed hundreds of email programs and services since 1997. lifewire's editorial guidelines Updated on November 27, 2021 Tweet Share Email Tweet Share Email MS Office Outlook Word Excel Powerpoint What to Know Open a message in Outlook. Select More Actions (the three-dot menu).Choose View message source to reveal the header information at the top of the email. This article explains how to see the full email headers in Outlook.com. This information applies to Outlook.com and Outlook Online. See Full Email Headers in Outlook.com When you want to trace spam to its source and report the spam to the internet service provider, or when you need to to see mailing list commands hidden in header lines, view the full headers for the message. By default, Outlook.com shows only a few important headers, but you can make it display all header lines. To access the full message headers in Outlook.com: Open the message whose headers you want to examine. Select More actions (the 3 dots ... in the upper right). Select View message source. The header information will be at the top of the email. You'll see not only the header information but HTML formatting for the email as well. Select Close when you finish viewing the header information. What Do Email Header Lines Look Like? An email's header lines can look like the following highlighted example below: Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit