Hi there, @claire-mignot-on.
You can run the Transaction Detail by Account report it includes the vat element in a different column. Let me show you how:
For additional resources, here's an article about customizing reports in QuickBooks Online.
You can memorise your report to save its current customization settings.
Also, I'm adding our website it provides tips on how to manage your account and help you with your future task in QuickBooks.
Please know that I'll be right here to help you if you have any other questions about running reports in QBO. I'll be here to lend a hand. Keep safe always.