Customer change order status by link via email

Hi everyone! I am making a woocommerce website where product are free. If anybody buy a “product” he got a seat at the event (events are the products). I have a problem becasue checkout at the moment is to easy for them. Do you know any way that after checkout there will be sending an email to them with the “accept” link or button (after clicking the link product will chagnge status to complete. Thank you for your anwser.