A controlled document is typically one that is Revision sensitive - BUT - Not always!!
If a controlled document is changed, a record of the change has to be made. This means we must have a History of All Changes.
If a document is changed, people who use it must know about the change. This means there has to be a distribution list or other effective way to let everyone who uses it know the document has changed.
Every employee must know how to check to see if documentation they are using is the most current version.