Woocommerce add custom field to cart?

Question

WordPress

I want to display in the cart (namely in cart.php) the amount of the additional fee (it costs on each product), but when I try to do this, nothing is displayed as standard.

Here is my custom field:

add_action( 'woocommerce_product_options_pricing', 'demolink_woo_add_custom_fields_2' );
function demolink_woo_add_custom_fields_2() {
  echo '<div class="options_group">';// Группировка полей
  
    // цифровое поле
    woocommerce_wp_text_input( array(
       'id'                => '_number_field',
       'label'             => __( 'Доп. сборы (%)', 'woocommerce' ),
       'placeholder'       => 'Ввод чисел',
       'description'       => __( 'Вводится в %', 'woocommerce' ),
       'type'              => 'number',
       'custom_attributes' => array(
        'step' => 'any',
        'min'  => '0',
       ),
    ) );
  
  echo '</div>';
  
}

// Сохраняем метаданные заказа со значением поля
add_action( 'woocommerce_checkout_update_order_meta', 'art_woo_custom_fields_save_2' );
function art_woo_custom_fields_save_2( $post_id ) {

  // Сохранение текстового поля.
  $woocommerce_number_field = $_POST['_number_field'];
  if ( ! empty( $woocommerce_number_field ) ) {
    update_post_meta( $post_id, '_number_field', esc_attr( $woocommerce_number_field ) );
  }
}

And this is how I'm trying to get it out

global $post, $product;
  $num_field      = get_post_meta( $post->ID, '_number_field', true );
      echo $num_field;

But nothing comes out, the value is not displayed, tell me pliz what's wrong?