You can view Wealth Builder PDFs from your mobile device however sometimes they're easier to view on a larger screen. To download or print a PDF from inside Wealth Builder on a larger screen, you'll need to access the app from a web browser (on a laptop or desktop device) by going to http://www.WealthBuilder.io. From there you can login and navigate to the PDF and then download or print it as usual. Alternatively, if you have an “AirPrint” compatible mobile device (on the same network as your printer) you can try that feature as well.
One note, if you're using Chrome and can't see the PDF, try another browser like Safari or Firefox (or try an Incognito window inside Chrome). Sometimes Chrome gets a little buggy lately with PDFs.