Record Document

A Record Document is an object this is uploaded or attached as per a Step Definition.  You can also attached a Document onto just about any other object.  This will become a Record Document also known as a Record Object.  

Record Documents are not meant to be revision controlled so they have fewer states.  You can view all of them using the Record Document Listbox.

Controlled Document

A Controlled Document is created using the Document Definition Form.  These are items that are meant to be Revision Controlled such as an Email Template or a Work Instruction.