If you're looking for a mass export to PDF, take a look here.
MOBILE DEVICES
Billdu uses the Print feature to save PDF files or send them to other applications.
Select an invoice or any other document, click on ... and select Print.
A preview appears
Now zoom the invoice (pinch to zoom) and a bigger preview appears.
There is an icon in the upper right corner (arrow in a box) - click on it
Now you can choose an app or a place where to save the PDF file
On Android devices click in the upper right row on the arrow icon and select Save as PDF
Click on the PDF download icon

WEBSITE
You can download a single file as a PDF instantly on the website. In the Document list in the Actions column click on ... and choose Download PDF.
