To export your newsletter as a PDF file:
Navigate to the Campaigns page.
Select the Sent tab.
Find the campaign you wish to export and click View report.
Select the View email tab.
Just above the newsletter and right by the Click map option, click on More.
Select Save as PDF.
A new tab showing the newsletter as PDF will pop up. Click on the download button, which is usually a downward-facing arrow.
You can also find a Save as PDF button on the top-right corner of the page when viewing the preview version of your newsletter on the Drag and drop editor.