Add tax to completed orders

Hi guys,

I am working on a woocommerce shop that has been getting orders since januari 2017. The owner of this shop hasn’t configured the taxes properly. Now he needs to make a tax report but there are no taxes included in the invoices that are generated from the plugin.

I have set up the taxes correctly now, all new orders show the taxes in the order page. My question: Is it possible to add the taxes to all of the completed (old) orders? If so, can anyone assist me with this?

Looking forward to hear from you guys, thanks in advance!