You can connect tickets to orders by making orders field in the ticket submit form required. You must have WooCommerce and Easy Digital Down addon installed in your site to use orders field. After a customer logins, all her orders will be populated in the ticket order field. After the customer chooses the order she wants to open a ticket for, the product field will be populated with the products in that order.
In addition, you can connect a ticket to an order after the ticket is submitted. Simply login to the WordPress dashboard and edit the ticket and connect the order from the Orders box. You can also create the same connection from WooCommerce or Easy Digital Downloads order using tickets box after editing the order record.