How to forward Message Headers

The header is the section of the email which details the path the email has taken to reach you.
Instructions for including the header in a forwarded email vary depending on which email handler you use:

Outlook 2013/2016

Right click on the message in the mailbox and choose View Source.

Apple Mail
 Double click on the message you wish to forward
 Select View from the menu bar
 Choose Message and Long Headers
 Click on the Forward button
 Send message as usual

Office365
 Go to https://outlook.office365.com and log in to your account
 Right Click on the email and click on view message details
 Highlight all of the contents of the message details box
 Right Click inside the box and copy the highlighted text
 Click Close
 Click Forward
 In the new message pane, right click in the text box and select paste to insert the full headers
 Forward the message to the appropriate email address or addresses