Add custom column to shop_order post type

functions.php

<?php
/**
 * Add custom column to shop_order post type
 *
 * @param   $columns    array    Array of all registered columns.
 *
 * @return  array $new_columns
 */
function add_custom_column_to_shop_order( $columns ) {
	$new_columns                 = is_array( $columns ) ? $columns : array();
	$new_columns['software_key'] = __( 'Chave' );

	return $new_columns;
}

add_filter( 'manage_edit-shop_order_columns', 'add_custom_column_to_shop_order' );