I appreciate you sharing your concern here in the thread, @niscliff.
Indeed, there are instances when we need to enter invoice numbers manually to track transactions seamlessly. Since the ability to turn off the custom transaction number isn't available in QuickBooks Online (QBO), I recommend sending a suggestion directly to our Product Development Team. They can consider your ideas while working on enhancing our product.
Here's how:
1. Head to the Gear icon.
2. Select Feedback.
3. Share your comments or product improvement ideas.
4. Click Next to submit.
You can stay updated on the progress of your feature requests by visiting our QuickBooks Online Feature Requests website.
In addition, you can review these articles to have an overview of personalizing sales forms and receiving invoice payments:
Feel free to visit the Community if you have additional questions regarding the custom invoice number or other related concerns in QuickBooks Online. We're always here to lend a hand.
