You can only upload a PDF to Facebook groups and business pages, unless you convert the PDF to an image file.

How to Convert a PDF File Into a Photo for Facebook Uploading. If you want to share a PDF such as a quarterly report on Facebook, you can just upload it as a document to a Facebook group.

How to Make a PDF Into a Link on Facebook. Linking to PDF documents on Facebook is one way to share information with friends and contacts. Facebook doesn't allow users to upload and embed PDF ...