Audit documentation, also known as working papers, consists of records of procedures performed by auditors during an audit, serving several critical purposes such as planning, accountability, and quality control. It is essential for auditors to document significant matters, ensure proper handling of working papers, and engage in professional judgment throughout the audit process. SQC 1 outlines the retention policies for audit documentation, emphasizing that it should be completed and assembled within seven years of an audit report, while maintaining professional skepticism and thorough communication within the audit team.