Represents the "AcroForm" entry of the catalog dictionary object.

It is an optional entry defined as part of the PDF 1.2 specification.

It contains an InteractiveFormElement.

The InteractiveFormElement contains the root of any field information for the document.

Fields are represented as an abstract tree structure of FieldElements, spanning the entire document.

Each field has a name and also a full name (like a file path) which tells you how to get to that field from the top level of the tree.

Fields are abstract - they hold a name and value - but they do not explictly have any ability to display themselves.

So to make them visible, leaf FieldElements need to be linked to WidgetAnnotationElements placed on individual pages of the document.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 28, page 74.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 3.25, page 23.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 29, page 99.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 242, page 458.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 245, page 555.