Cómo mostrar las etiquetas dentro de los campos al finalizar compra en WooCommerce

    <?php
    /* Etiquetas de los campos dentro del campo al finalizar compra */
    add_filter( 'woocommerce_checkout_fields', 'etiquetas_dentro_finalizar_compra', 9999 );
    function etiquetas_dentro_finalizar_compra( $fields ) {
        foreach ( $fields as $section => $section_fields ) {
            foreach ( $section_fields as $section_field => $section_field_settings ) {
                $fields[$section][$section_field]['placeholder'] = $fields[$section][$section_field]['label'];
                $fields[$section][$section_field]['label'] = '';
            }
        }
        return $fields;
    }