You can use System–Audit Control menu to enforce transaction control and log user activities.
Enforce transaction reversal for all dates
You can check this option to prevent any change to any transaction. You can however add a reverse transaction to correct some mistake. This option is highly recommended.
Close Books up to
When you close books upto a certain date, system does not allow changing any transaction prior to this date. Please note that this is not a year end process.
Activate Audit trail
All user activity (adding, changing, deleting transactions) is logged. You can view this log using 'Others–Audit Trial' report.
Remove Audit trail up to
You can use this option to remove audit trail from database up to a certain date. Useful to make your backups small.