Do we have a control in place to avoid duplicate Journal Voucher number

Welcome to the Community space, @. I'll gladly provide information to help you avoid duplicate journal voucher numbers inside QuickBooks Online (QBO).

When creating a journal entry inside QBO, there's an option that you can use to notify you if the journal number is already in use. We'll outline the steps to help you set it up inside the program:

1. Access your QuickBooks Online company.
2. On the left navigational bar, click the +New button.
3. Select Journal entry.
4. On the top right corner, click the Gear icon.
5. Tick the box beside Warn if duplicate journal number is used.
6. Click the Turn on setting button.
7. Add the necessary details inside the journal entry and then click Save or Save and new button once done.

Furthermore, here's an article to help you deal with handling created journal entries and manage users inside QBO:

• Reverse or delete a journal entry in QuickBooks Online
• Add and manage users in QuickBooks Online

We're excited to welcome you back if you have any more questions about QuickBooks or require assistance with journal entries in the program. Stay safe, and have a great day!