VAT obligations for marketplaces as of July 1, 2021
Professional sellers (located worldwide and subject to VAT) are obliged to apply the VAT rate of the consumers country if they realize a turnover (excluding VAT) higher than 10 000 € (on all platforms on which a vendor/provider could offer its services) for their activity of distance selling of goods or services supplied by electronic means.
The VAT rates to be applied on your customers invoices are listed on the European Community website: https://ec.europa.eu/taxation_customs/tedb/vatSearchForm.html
It is your responsibility to respect the European laws and directives for your sales.