My invoices on quickbooks do not have a section for customer order number, how do I alter this? Thanks

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:

1. Go to the Gear icon, then select Custom form styles under Account and settings.
2. Look for the template you're using from the result.
3. Click on Edit under Action to customise the form.
4. Tap on Content, then click on the upper part of the Preview page.
5. Under Form, check the box beside Form numbers to add the number on the form.
6. Hit Done to save the changes.

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!