I appreciate you for reaching out to us here on the Community page, @techplasuk.
I'll share some steps on how to add the customer order number or transaction number on your invoices/transactions in QuickBooks Online (QBO).
You can just customise your template to add the number on your forms, here's how:
For additional reference about customising form templates in QBO, check out this article: Customise invoices, estimates, and sales receipts in QuickBooks Online.
Add a comment below if you have additional concerns. I'm here to keep helping. Have a great day!
Hi there, @Stanlio.
I'm happy to know that the solution shared by my colleague Angelyn_T above help you with your concern.
Please know that the Community team is always here to help you with any concerns you may have with QuickBooks Online. Wishing you all the best, @Stanlio.
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