How to add custom columns to the order item table on the WordPress backend?

The code below will add a custom column in order details view in the order items table like in the image below. If you have created a child theme then add the code in the function.php file of your child theme.

  // Add custom column name in table header
  add_action('woocommerce_admin_order_item_headers', 'my_woocommerce_admin_order_item_headers');
  function my_woocommerce_admin_order_item_headers() {
  	// write column name
    $column_name = 'Column A';

	// display the column name
    echo '<th>' . $column_name . '</th>';
  }
  
  // Add custom column values in table
  add_action('woocommerce_admin_order_item_values', 'my_woocommerce_admin_order_item_values', 10, 3);
  function my_woocommerce_admin_order_item_values($_product, $item, $item_id = null) {
  	// get the custom field value using product id
    $custom_field_Data = get_post_meta($_product->post->ID, '_custom_field_name', 1);

	// print the value
    echo '<td>' . $custom_field_Data . '</td>';
  }