Elements

Use the WithholdingTaxTotal element to model the tax details:

Element	Description
Tax Amount (`Invoice/WithholdingTaxTotal/TaxAmount`)	The total withheld tax amount.
Description (`Invoice/WithholdingTaxTotal/TaxSubtotal/UBLExtensions/UBLExtension/UBLExtensionContent/ WithholdingTaxSubtotalExtension/Description`)	Text description of the withholding tax category.
Subtotal Tax Amount (`Invoice/WithholdingTaxTotal/TaxSubtotal/TaxAmount`)	Withheld tax amount of the current breakdown.
Tax Category ID (`Invoice/WithholdingTaxTotal/TaxSubtotal/TaxCategory/ID`)	Category and withholding tax code applied to the respective subtotal. You must use `IRF`.
Tax Scheme ID (`Invoice/WithholdingTaxTotal/TaxSubtotal/TaxCategory/TaxScheme/ID`)	Tax scheme not required in Portuguese context, but mandatory for syntactical reasons. Provide value: `VAT`.

Use the Description (Extn) Extension to add the description:

Element Name (Path)	Element Description
Withholding Tax Description (`Invoice/WithholdingTaxTotal/TaxSubtotal/UBLExtensions/UBLExtension/UBLExtensionContent/ WithholdingTaxSubtotalExtension/Description`)	A description for the withholding tax.

Restrictions

You must use IRF for the TaxCategory/ID element.
You must use VAT for the TaxSchemeID element.

Example

<ubl:Invoice>
    <!-- Code omitted for clarity -->
    <cac:WithholdingTaxTotal>
        <cbc:TaxAmount currencyID="EUR">10.00</cbc:TaxAmount>
        <cac:TaxSubtotal>
            <cec:UBLExtensions>
                <cec:UBLExtension>
                    <cec:ExtensionContent>
                        <vrbl:WithholdingTaxSubtotalExtension>
                            <cbc:Description>Withholding tax description</cbc:Description>
                        </vrbl:WithholdingTaxSubtotalExtension>
                    </cec:ExtensionContent>
                </cec:UBLExtension>
            </cec:UBLExtensions>
            <cbc:TaxAmount currencyID="EUR">10.00</cbc:TaxAmount>
            <cac:TaxCategory>
                <cbc:ID>IFR</cbc:ID>
                <cac:TaxScheme>
                    <cbc:ID>VAT</cbc:ID>
                </cac:TaxScheme>
            </cac:TaxCategory>
        </cac:TaxSubtotal>
    </cac:WithholdingTaxTotal>
    <!-- Code omitted for clarity -->
</ubl:Invoice>