PDF documents created in Acrobat 5.0 or later contain document metadata in XML format. Metadata includes information about the document and its contents, such as the author’s name, keywords, and copyright information, that can be used by search utilities. The document metadata contains (but is not limited to) information that also appears in the Description tab of the Document Properties dialog box. Document metadata can be extended and modified using third-party products.
The Extensible Metadata Platform (XMP) provides Adobe applications with a common XML framework that standardizes the creation, processing, and interchange of document metadata across publishing workflows. You can save and import the document metadata XML source code in XMP format, making it easy to share metadata among different documents. You can also save document metadata to a metadata template that you can reuse in Acrobat.