How to customize a credit note?

Hello there, abidalam1218-gma.

I can share some insights about your concerns in customising a Credit note in QuickBooks Online.

You can only customise an Invoice, Estimates, and Sales Receipts in QBO. 

You may consider looking for a third-party app that can integrate with QuickBooks Online. This way, you'll have the option to customise the credit note. Just go to the Apps menu or through the QuickBooks App Store.

Find the app within your QBO account: 

1. Go to the Apps menu.
2. Look for the appropriate app through the Search by name or category field or using the Browse category button. 
3. Click the app so you can check more details.

You can also check these articles about customising sales forms as well as creating and applying credit memos or delayed or delayed credits in QBO:

• Customise invoices, estimates, and sales receipts in QBO.
• Create and apply credit memos or delayed credits in QBO.

Let me know if you have other questions about managing your transactions in QBO. I'm just here to help. Take care!