Hi, @carout.
You can modify your invoice template to remove the VAT summary on your invoices. I'll help you how.
- Open your QuickBooks Online (QBO) account.
- Go to the Gear icon, then click on Custom Form Styles.
- Click the Standard template or the template you're using.
- Hit the Content tab.
- You'll see a sample invoice on the right side. Click on the bottom part of it.
- Remove the check-mark beside the VAT summary under the Display section.
- Select Done to record the changes.

For more options about customising your form templates, you can check out this article: Customise invoices, estimates, and sales receipts in QuickBooks Online.
Moreover, here's how you can manage your sales and customer's transactions in QuickBooks Online.
If you have any other questions about removing vat summary on invoices, let me know by adding a comment below. I'm always here to help. Have a good one!