A more thorough explanation:

An audit trail is a record of all the steps taken to verify and validate financial transactions. It is a chain of evidence that connects account balances to original transactions and calculations. The purpose of an audit trail is to provide a clear and complete picture of how financial data was created, processed, and reported.

• When a company receives a payment from a customer, the payment is recorded in the accounting system. The audit trail for this transaction would include the original invoice, the payment receipt, and any other supporting documents.
• When an employee submits an expense report, the audit trail would include the receipts for each expense, as well as any approvals and reimbursements.

These examples illustrate how an audit trail provides a clear and complete picture of financial transactions. By following the audit trail, an auditor can verify that the transactions were properly recorded and that the resulting account balances are accurate.