- Open the email you would like to attach
- Open the menu on the right and select "Show Original" - (It will open a new window with the message in plain text)
- In your browser, select "Save As" and use the .eml extension.
NB: This will create a message that all mail clients (Outlook, Live Mail, Thunderbird...) can open, and it will include all original headers. Then upload that .eml file as an attachment to the message you're sending.
B) Attach as a Google Drive HTML file:
- Open the email you would like to turn into an attachment.
- Click the drop-down next to ‘Reply’ in the top-right corner of your message.
- Select ‘Print’.
- On the left-hand side of the print screen, click the ‘Change’ icon in the ‘Destination’ section.
- Select the option to ‘Save to Google Drive’ in the ‘Google Cloud Print’ section.
- Click ‘Save’ at the top of the print screen.
- Open / Create the new message you would like to send.
- Attach your old message using the ‘Insert Files using Drive’ icon.
- Select ‘My Drive’.
- Find your old email in Drive (it should be at the top of the list) and select it.
- Your old email is added as an attachment!