Thanks for asking us here in the Community, @Accounting646. We can set your numbering preference using the Custom transaction numbers feature.
Then, you can add an Invoice no. field where you can enter any number format you want. Here's how:
- Go to the Gear icon, then select Account and Settings.
- Select Sales, then click t anywhere within the Sales form content section.
- Turn on Custom transaction numbers, then select Save and then Done.
Once done, open an invoice, and enter the sequence starting with 1 in the Invoice no. field. It will set the sequence and applies it to all sales forms.
For future reference, you'll want to check out this article to learn more about customizing your invoice and sales forms in QuickBooks Online.
Feel free to ask some more, and I'll make sure to answer them for you. Take care!