You can list document properties for a PDF document found in the Document Information Dictionary.
The properties stored in the Document Information Dictionary are are presented as a series of name/string couplets, each one a key with a value. Many of these properties are defined by Adobe Acrobat, but you can create custom PDF properties for the Document Information Dictionary for internal use.
See Section 14.3.3, “Document Information Dictionary,” in the ISO 32000 Reference, page 549.
If you know the name of the key for the property you are looking for, you can use either of these methods to obtain the value associated with that key:
Obtain the Document Information Dictionary as a COS object using CosDicGetInfoDict(PDDocGetCosDoc()).
You may then enumerate this dictionary to find all of the properties and values.
Properties can be set via PDDocSetInfo().