Hi there, Chris.

I'll provide information about modifying the invoice number in your recurring template in QuickBooks Online (QBO).

In QBO, our invoicing system generates invoice numbers in a specific order. It's important to note that there's no way to have different sequence numbers for invoices from different sources (ABC and XYZ). This is because the system will automatically generate invoice numbers based on its sequence, regardless of the source.

If you need to have a different sequence for your invoices, I recommend manually editing the invoice number as a workaround. But before doing so, ensure to turn on the custom transaction number. Here are the steps to follow:

1. Click on the Gear icon.
2. Select Account and Settings.
3. Choose the Sales menu.
4. Click the Custom transaction numbers button in the Sales form content.

To edit the invoice number, please see this article:

1. Go to the Sales menu, then choose Invoices.
2. The invoice window appears with the list of invoices created so far.
3. Find the invoices in question.
4. Click on Edit in the Action column.
5. Update the invoice number.

Additionally, I've added this article to help you gently remind customers about invoice due dates to ensure you're paid on time: Send invoice reminders automatically or manually in QuickBooks Online.

Fill me in if you have more queries about any invoice-related topics. Simply tap the Reply button below, and I'd be glad to assist you further. Take care.