If you’re using an iPhone model 6s onwards, then you’ll be able to use the 3D Touch functionality to do all sorts of commands, depending on the app you’re using. Introduced in June 2016, 3D Touch allows users to select from different options depending on how hard they press down on the phone screen; for example, a slight touch on an email in the Mail app will open a preview, whereas a slightly harder push will open the message completely. This feature is used across a wide range of apps for different purposes, one of the most common being the “Print” function.
Whether you want to do a direct print or Print to PDF, the basic steps are the same. Each app supports this feature differently (if at all), but the 3D Touch feature adds an extra element, as typically you will be able to hard push (“Pop”) on the page or image you want and the option to Print will come up. This will then let you select your printing options and either print a direct copy or print to PDF and save the file elsewhere on your device for later viewing/physical printing. Users most commonly save to iCloud, iBooks, Kindle or Dropbox to view the PDF and print at a later date.