What is the difference between controlled copy and un-controlled copy?

Controlled copy: A controlled copy is a formal copy of the latest, correct issue of a document; an identified issue of a document to an individual or location of the record. The controlled copy is officially tracked, updated & destroyed to assure that it is current.

Uncontrolled copy: An informal copy of a document for which no attempt is made to update if after distribution; the document is marked “uncontrolled” and the user determines if the document is active prior to use. Controlled and uncontrolled copies of the documents are issued by the quality assurance department as per the official requirements. Uncontrolled copies are unofficial copies of documents generally, issued for review purpose.