Add a note if product is set as no-tax

… or better would be to add the html text only when “that” single product is sold…

Is this what you are looking for? https://docs.wpovernight.com/woocommerce-pdf-invoices-packing-slips/pdf-template-action-hooks/#example-2-print-a-custom-text-after-the-order-details-table (3rd version)

If this is applies to all countries including the base country, you could simplify the code:

add_action( 'wpo_wcpdf_after_order_details', 'wpo_wcpdf_tax_exempt', 10, 2 );
function wpo_wcpdf_tax_exempt( $document_type, $order ) {
    // only in financial documents
    if ( !in_array( $document_type, array('invoice', 'proforma', 'credit-note') ) ) {
        return;
    }
     
    // check if any tax was charged
    if ( $order->get_total_tax() == 0 && $order->get_total() > 0 ) {
        ?>
        <div class="tax-free">
        Tax free order.
        </div>
        <?php
    }
}

Hi, it seems to be what I need, I’ll try the code now