account admin confirm email enabled generated includes level link preferences product purchase redirected redirection referring send system thank-you thank-you-page turn url user

Currently the email generated by the system includes a link to confirm the purchase. How do I turn this off so that the system does not send that link?

I think you are referring to the link to "complete purchase" that goes in the "thank you" email. That will only happen if you have enabled "redirection" for each product.

If you don't want that link and want the user to be redirected to you own thank you page still, you should use the redirection on account level. That URL goes in Admin > Preferences.