In the Premium (and Secure) version of the plugin, an optional Download button appears in the toolbar. Users can download the PDF to their computer, open it to browse using their default PDF viewer, and print from there.
However, no version of the plugin has a direct 'print' button in the embedded viewer's toolbar in your WordPress site.
Some users also ask if the Secure version allows a PDF to be printed but still make downloads difficult.
It can never be possible to allow printing but not downloading because most browsers will allow the user to "print as PDF". This has exactly the same effect as downloading the file - so you can't really have print functionality without download being just as easy.