It‘s not zero VAT. It just reverses who has to pay the VAT. E.g Microsoft invoices me at 0% VAT but I have to report and pay 19% to the state. (b2b only)
What happens is that you debit and credit the same VAT amount in the books, effectively deducting and zeroing it immediately.
https://europa.eu/youreurope/business/taxation/vat/cross-bor...
Which is the stupidest system internally : get paid vat, paid it to the state minus the VAT you’re owned as business for whatever you’ve bought. Loss of time and energy all around.