Embodiments herein include a content manager that constructs vocabulary from the PDF form fields to classify documents. The content manager can associate a PDF form with a markup language schema (such as an XML Schema) so that PDF form fields are semantically bounded with XML schema elements. The XML schema elements can define semantics of form fields and specify other constraints on XML elements and attributes. The content manager then associates selected form fields from the PDF form with a content folder to construct a set of properties to apply to inbound PDF form data to classify documents.