Open the email in Gmail and click the icon (top-right corner).
While not a .txt file, Gmail's native download feature saves the email in format, which is a raw text-based format readable by most text editors. Open the email.
You can then right-click the downloaded file and select (or any text editor) to view the raw content.
Right-click the PDF in Drive and select .
In the Google Doc, go to . Method 3: Native "Download Message" (Standard EML)