How do I configure DPH 21% / 15% / 10% + reverse-charge for EU B2B?

Czechia has three DPH rates:

• 21%, standard rate (most goods + services).
• 15%, reduced (food, water, books, some pharmaceuticals, child seats, accommodation services).
• 10%, super-reduced (life-saving medicines, baby food, certain printed materials, gluten-free products since 2024).

Magento configuration:

1. Create 3 tax classes in Stores → Tax Zones & Rates (DPH-21, DPH-15, DPH-10).
2. Create 3 tax rules per rate, scoped to CZ (or EU + auto-detect via destination).
3. Assign each product’s tax class based on its category, we usually wire this via a category_id → tax_class map in an observer (so admins don’t need to set it per product).
4. For B2B intra-EU, override to 0% DPH (reverse charge) if a valid VIES-validated DIČ is on the customer. Magento needs to print “Přenesená daňová povinnost” (reverse charge) on the invoice with a reference to § 92e of the Czech VAT Act.
5. For sales to non-VAT-registered EU customers above the OSS threshold (€10k / year EU-wide), register for One-Stop-Shop and charge destination-country VAT.

Tax-inclusive prices on storefront (mandatory in EU B2C); tax-exclusive on B2B if explicitly opted-in.