Thanks for taking the time to post on the QuickBooks UK Community Page, I hope you'll take full advantage of these pages on your own QuickBooks Journey.
I'm going to direct you to this link https://www.gov.uk/guidance/vat-exports-dispatches-and-supplying-goods-abroa My entire understanding of VAT on exports abroad is found from that article, i'll elaborate what i know at the moment.
My understanding of charging tax on customers in the EU is that you use 20% Standard VAT for any customer who is not VAT Registered and if 20% S is normally used for the same sale to a UK Customer. When however, you're dealing with a VAT Registered company you'd use the 0% ECG or ECS codes so that the purchaser of your goods/services can account for VAT at their own acquisition rate.
If you're unsure of anything i've told you, you can always call HMRC and inquire with them, but I'd reach out to your accountant for an answer.
You're asking the question in the right place, there are some Accountants users and Community hosts alongside other users who can help too.