QuickBooks Online maintains an Audit Log of each financial transaction as it is added, changed or deleted. This “audit trail” lets you see who made the changes and exactly what changes were made throughout the history of a transaction. The Audit Log is easy to use.
Choose Gear Icon > Audit Log.
From any listed transaction, click the work View under the History column. This will take you to its Audit Log page. Data that was changed will be highlighted.