Modifying this control will update this page automatically
![](https://help.apple.com/assets/61DC8A1AC689DE6B7F17E3B8/61DC8A1BC689DE6B7F17E3BF/en_US/fcdf74cf8457ce188a2aaa7cf1293c83.png)
Show detailed headers in Mail on Mac
When you view an email message, you can show more fields in the message header, such as List-ID or Resent-From.
In the Mail app
on your Mac, choose View > Message > All Headers.
To view fewer header fields again, choose View > Message > Default Headers.
You can specify additional fields to show in default headers in Viewing preferences in Mail.