This is not related to Reader, and can't be solved using it, as it is unable to create or edit PDF files in such a way.
You need to look for this setting in the application you're using to scan the documents. It's probably set to apply a password there.
As I said, you can't remove that password with Reader. You will need Adobe Acrobat to do it (or some other capable application).
Make sure you recognise when the SYSTEM is asking for a password, and when an APP is asking for a password. If you can't tell the difference, you are sure to be tricked by bad software at sometime...
So, what are the exact words in the password message? (Leave out any personal info). We may be able to recognise what is going on. If it's asking for the system password, then it isn't PDF passwords at all...
Thanks for that. The Scanner app doesnt have anywhere to change settings. Its called NAPS (Not another PDFScanner) its pretty basic but works. I have uninstalled it and reinstalled it and no change.
In that case you'll need to answer the questions asked by TSN above, as it's not possible that Reader is adding password protection to the files.