Document types are document properties that uniquely categorizes a document so that it is similar to the document's drawer or folder, regardless of the document's folder or drawer location.
You assign the document type when capturing the document or when you define its properties, and you can also modify the document type after it has been initially assigned. However, you can assign only one document type to a document.
Document types can include custom properties, which are additional properties to which you can assign values.