documents require password to open

[MPADB]

why do I have pdf documents in my cloud that need a password to open?

[JasonB_VZW]

That is a very good question, as Verizon Cloud does not have a password to open option other than the Private Folder.
I believe what you are seeing is a PW-Locked document in of itself.  Cloud does not have a PDF reader built in, and relies on the device to launch an app to read the document.  If the document itself were locked, then the app opening it would present the unlock to the user on open.