To view your invoice, go into your emailed receipt and click on View My Orders:
You can also click on View My Orders from your order confirmation page:
From there, it is going to prompt you enter the email address associated with your account:
You will receive an email from TechSmith Corporation <firstname.lastname@example.org> with a link to manage your orders.
You should then be taken into your account to manage your orders. At the bottom of this page is the link to your Order Invoice: