Does QuickBooks Online have Accounts Payable duplication invoice number notice?

Hello there, Erin. 

Yes, QuickBooks Online (QBO) offers a helpful feature to prevent duplicate invoice numbers by triggering a warning.

To activate this feature, select the setting labeled Warn me if I enter a bill number that is already used for that supplier. It prompts you with a notification when you attempt to create a duplicate invoice number in Accounts Payable (bills).

To enable it, follow these steps:
 

1. Click the Gear icon and select Account and Settings.
2. Go to the Advanced tab on the left menu.
3. Locate the Other preferences section and click on Edit.
4. Please turn on the option Warn me when I enter a bill number that is already used for that supplier.
   
   
    
5. Click Save, then Done.

By managing duplicate AP invoice numbers in QBO, businesses can ensure financial accuracy, avoid overpayments, mitigate cash flow challenges, and safeguard against fraud while maintaining efficient AP operations. If you need further assistance with this feature or any other aspect of invoice management, feel free to reply to this thread. I'm happy to help.