Outlook Web App (OWA)

1. Right-click on the e-mail for which you would like to have the header lines displayed.

2. Select Show message details in the drop-down list.

3. A Message details window opens, which contains the header lines.

4. If you would like to forward the data, copy it completely into a text file and paste it into the attachment of an e-mail.
    

Outlook (Windows)

1. Double-click on an e-mail message to open it outside the reading pane.

2. Click on File.

3. Click on the Properties box.

4. The header information is displayed in the Internet headers box.

5. If you want to forward the data, copy it completely into a text file and paste it into the attachment of an e-mail.

Outlook (macOS)

1. Right-click on the mail for which you would like to have the header lines displayed.

2. Select Show source from the drop-down list.
   A new window opens with the header lines. 

3. If you want to share the data, copy it completely into a text file and paste it into the attachment of an e-mail.

    

Thunderbird

1. Double-click on an e-mail message to open it outside the reading pane.

2. Click on More at the top left.

3. Click on Show source text.

4. The header lines are now displayed in the new window.

5. If you want to pass on the data, copy it completely into a text file and paste it into the attachment of an e-mail.
    

Apple Mail

1. Select the e-mail for which you would like to have the header lines displayed.

2. Click on View at the top of the bar.

3. Select Email from the drop-down list.

4. Click on All headers.

5. If less data is to be displayed, repeat the process described.

6. Otherwise, you can also press the key combination Shift+Command+h.

7. If you want to share the data, copy it completely into a text file and paste it into the attachment of an e-mail.