QuickBooks comes with a feature called the Audit Trail, which is a report that provides a detailed listing of all the transactions and changes to transactions made in your QuickBooks file. An accountant trying to trace activity in his client's QuickBooks files might find the Audit Trail indispensable as a tool for identifying when changes occurred, and internal auditors also will find this tool to be essential.
If more than one person has access to a company's QuickBooks file, the Audit Trail provides a certain amount of security in that no changes can be made to any forms or amounts in your file without a record of the changes and who made them appearing in the Audit Trail.
The Audit Trail works completely in the background and doesn't interrupt your day-to-day QuickBooks activities.
Starting with the 2006 version of QuickBooks, the Audit Trail feature is always turned on.