Mafuba

Hello, I am living in the Netherlands and creating a website similar to Fiverr, targeting users within the EU. I am using WooCommerce as the payment service. In this business model, there are three roles: operator A, seller B, and buyer C. When C purchases a digital content product from B, A receives a 10% fee as commission. I have some questions regarding taxes: Is it correct that "if B and C are in different EU countries, the VAT rate depends on C's country of residence"? How should B file their tax returns? Thank you for your assistance.