Hi there, MitziS,

I can provide you some information about this question.

You can find the Customer Transaction Number preference in the Accounts and Settings section in QBO. Let me guide you how to get there:

1. Click the QuickBooks Gear icon.
2. Select Account and Settings.
3. Click the Sales tab.
4. Click the Sales form content section.
5. Uncheck the Custom transaction numbers box.
6. Click Save, then Done.

That should do it, MitziS. Please keep me posted if you have any questions with QuickBooks. All the best!