Checkout Field Manager

Hello,

I use GP Premium and WooCommerce for my website and I would like to add a text field to the WooCommerce order validation form. I’ve installed the Checkout Field Manager plugin but I can’t display the field.

I’ve tried directly in PHP in the functions.php file (thanks ChatGPT), but that doesn’t work either.
Do you have any ideas? Are the hooks compatible with the theme?

Thanks

PHP :

// Ajouter un champ personnalisé à la page de commande
add_action('woocommerce_after_order_notes', 'custom_checkout_field');

function custom_checkout_field($checkout) {
    echo '<div id="custom_checkout_field"><h2>' . __('Code d\'authentification') . '</h2>';

    woocommerce_form_field('custom_code', array(
        'type'          => 'text',
        'class'         => array('custom-code-class form-row-wide'),
        'label'         => __('Entrez votre code'),
        'placeholder'   => __('Code composé de lettres et de chiffres'),
        'required'      => true,
    ), $checkout->get_value('custom_code'));

    echo '</div>';
}

// Valider le champ personnalisé
add_action('woocommerce_checkout_process', 'custom_checkout_field_process');

function custom_checkout_field_process() {
    if (empty($_POST['custom_code'])) {
        wc_add_notice(__('Veuillez entrer un code d\'authentification.'), 'error');
    } else {
        if (!preg_match('/^[a-zA-Z0-9]+$/', $_POST['custom_code'])) {
            wc_add_notice(__('Le code doit être composé uniquement de lettres et de chiffres.'), 'error');
        }
    }
}

// Enregistrer la valeur du champ personnalisé dans les données de la commande
add_action('woocommerce_checkout_update_order_meta', 'custom_checkout_field_update_order_meta');

function custom_checkout_field_update_order_meta($order_id) {
    if (!empty($_POST['custom_code'])) {
        update_post_meta($order_id, '_custom_code', sanitize_text_field($_POST['custom_code']));
    }
}

// Afficher la valeur du champ personnalisé dans l'administration des commandes
add_action('woocommerce_admin_order_data_after_billing_address', 'custom_checkout_field_display_admin_order_meta', 10, 1);

function custom_checkout_field_display_admin_order_meta($order) {
    $custom_code = get_post_meta($order->get_id(), '_custom_code', true);
    if (!empty($custom_code)) {
        echo '<p><strong>' . __('Code d\'authentification') . ':</strong> ' . esc_html($custom_code) . '</p>';
    }
}