To view the headers:

1. Log into Outlook on the web.
2. Go to Mail.
3. Open/View the message that you want to view the headers of.
4. Within the message, click on the "..." (three dots) next to the "Reply/Reply all/forward arrow" action button and select View | View message details. The 'Message details' window will appear containing the header information of the message.

To send as an attachment:

1. Log into Outlook on the web.
2. Select the message you want to forward as an attachment.
3. Click ... (More actions) located next to the sender/subject of the message.
4. From the drop down menu, select Other reply actions | Forward as attachment.
5. Enter any other relative information and click Send button.

To view the Headers

1. Open up a message by double-clicking on it.
2. Click File tab in the top left of the message.
3. Choose Properties from the bottom of the list and you'll see Internet Headers listed at the bottom

To send as an attachment

1. Open up a message by double clicking on it.
2. Within Message tab, in the 'Respond' group, click on More to get a drop-down option of forwarding/sending as an attachment.
3. Enter any other relative information and click Send button.

To view the source

1. Right-click the message within your folder listing.
2. Select "View Source" from the drop-down menu. A window will open showing the header information of the selected message.

To forward a message as an attachment

1. Click HOME tab.
2. Select Message.
3. Click the "Forward this message as Attachment" button from within the ribbon bar to forward the message as an attachment.
4. Enter any other relative information and click Send button.