Unable to edit pdf on tablet due to privacy settings.

I'm trying to edit (as in highlight and add messages) to a pdf on my tablet, but whenever I press the pen button it says that it is a read-only pdf and the tool is unavailable due to the document's security settings. However, when I go on my laptop, it works just fine and I am able to edit the same document. Why is this? And how can I change it so that I can edit the pdf on my tablet? I got downloaded the pdf online on my laptop, uploaded to Google Drive and tried to edit it through the Google Drive within Adobe Acrobat and also by downloading it to the tablet itself, but it won't work. I know any passwords for the permissions of the document, but surely if I don't need them on my laptop, I shouldn't need them on my tablet?