See Full Message Headers in Mail at iCloud.com

Every email contains a header, a list of information that details the origin, destination, time, program, and other metadata about that email. Your mail at iCloud.com is no different.

Specifically, a header includes some or all of the following, plus much more:

• The sender
• The recipient
• Date sent
• The subject
• CC (carbon copy), if applicable
• BCC (blind carbon copy), if applicable
• The time sent
• The time received
• The sender's location
• The email service used to send it
• Routing details

Such information can be useful in many ways. For instance, it can help you spot junk email and scams.

Much of this information is hidden by default, but iCloud Mail at icloud.com makes it easy to uncover. Here's how:

• Double-click the desired message to open it in a new window.
• Click the gear button in the message's toolbar.
• Select Show Long Headers from the menu that comes up.