Display Fields in input of tab product detail when have meta key

// Display Fields
add_action('woocommerce_product_options_general_product_data', 'woocommerce_product_custom_fields');
// Save Fields
//add_action('woocommerce_process_product_meta', 'woocommerce_product_custom_fields_save');
function woocommerce_product_custom_fields()
{
    global $woocommerce, $post;
   

    echo '<div class="product_custom_field">';
   // echo get_post_meta( $post->ID, '_supplier' ,true)  . "aa";  
    // Custom Product Text Field
    woocommerce_wp_text_input(
        array(
            'id' => '_supplier',
            'placeholder' => '',
            'label' => __('Lieferant', 'woocommerce'),
            'desc_tip' => 'true'
        )
    );
    echo '</div>';
}