Every line of an e-invoice carries an EN 16931 VAT category. Lines with a VAT rate above 0% are always category S. For 0% lines the plugin picks the category from the trade, unless you set one per tax class:
| Category | Used for | Picked on its own when |
|---|---|---|
| S | Standard and reduced rates | The rate is above 0% |
| K | Intra-community supply of goods | EU business buyer with a VAT number in another EU country, physical product |
| AE | Reverse charge | Same as K, for virtual and downloadable products |
| G | Export outside the EU | The delivery country is outside the EU |
| Z | Zero rated goods | Domestic 0% line and you have a VAT number |
| E | Exempt from VAT | Domestic 0% line and you have no VAT number (small business) |
| O | Outside the scope of VAT | Only when set by you |
Categories that need an exemption reason get the official VATEX code and the reason text you set. Shipping and fees become their own lines, coupons are applied the way WooCommerce applied them, and negative fees become a document discount. If the order total and the calculated total differ by a cent, the cent is carried in the rounding field, so the XML total always matches the order.
