How can I customize the invoice number to start back from 1001? And following invoices will automatically fill in the order from 1001.Now my quickbook remember 1074 upto

You'll need to enable to Custom transaction numbers option in QuickBooks Online (QBO) to use a different invoice number, @hoanglan-alan-vn. I'll walk you through the steps on how to proceed.

Here's how:

1. Go to the Gear icon, then select Account and settings.
2. Move to the Sales tab.
3. Click the Sales form content section.
4. Enable Custom transaction numbers.
5. Hit Save, then Done.

You can then change the invoice number from the Invoice no. box located on the upper right. See the screenshot below for reference:

If you change the invoice number to 1001 and you still have the original transaction, it will turn the new one into a duplicate. You'll see this message:  

I'll share this article with you: Customize invoices, estimates, and sales receipts in QuickBooks Online. It's a step-by-step guide on how you can edit sales form templates to your liking.

Post a comment if you have other questions about invoice numbers in QBO. I'll get back to you as soon as I can. Have a great day!