Follow along with the video below to see how to install our site as a web app on your home screen.
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This video shows you how to unlock a secured PDF file, then the file become editable and printable. I did it many times. The "Document open" password is a different thing.This only works if you lock the permissions of the file and when you do that, Adobe also warns you that the permission lock can be bypassed by other programs.
The permissions password lets you open the PDF, but you get restrictions on printing, copying etc.
The video is misleading.
If you put an actual "Document Open" password, you are dealing with 128-bit or 256-bit AES encryption (depending on settings), so a random online tool isn't going to help you.