Hello there, @listari.

Currently, showing the tax per item in your invoice is not possible in QuickBooks Online (QBO). We can only use one tax code per invoice or sales transaction.

In the meantime, you can look for a third-party app showing the tax amount per item and the list of line-level tax codes.

Here's how:

1. Go to the Apps menu.
2. Click Find apps.
3. Look for an app that can suit your needs in the search bar.

Lastly, check out these pages below about handling taxes, sales forms, reports, and other related matters. 

• QBO Singapore User Guide
• Customise invoices, estimates, and sales receipts

Leave a comment below if you have further questions about your taxes. I'm happy to help you again. Take care.