If you have a PDF document you can open it in several ways: (You can read the protected document if you have owner´s permission)
– If you have install Prot-On in your device: Download Here
Click on the document with the right button of the mouse and select “Open with…Prot-On”
– If you want to see it online:
Another way to open it is by dragging the protected document to Prot-On’s online viewer, Drag’n Drop, window.