An audit trail is a record or documentation that shows the history and activity of an organization, system, or individual. It typically includes information about who did what, when they did it, and any changes made to data or systems along the way. Audit trails are often used in accounting, finance, and computer security to track transactions, detect errors or fraudulent activities, and provide evidence of compliance with regulatory requirements. In essence, an audit trail serves as a paper (or digital) trail that can be followed to verify the accuracy and integrity of information, processes, and systems.