Adding a PDF file to Facebook Page is very easy, use Kagoon
Here’s a snap shot of my pdf uploads using Kagoon
Or if you would like to add Facebook Tab to upload your PDF you can go to this site https://www.facebook.com/pdf.tab and install onto your page
Down side of this facebook app is you only one tab instead of uploading several pdf files. I much prefer Kagoon.
What are you using to upload pdf to facebook?