Are you an Advantage account member (annual subscription) and asking how to change your product selection for the upcoming 2019 product? If so, there should be a tab in your account to change your product.
See this FAQ:
https://ttlc.intuit.com/community/choosing-a-product/help/how-do-i-update-or-confirm-the-info-in-my-...
Even if you order a CD, you will also receive a complimentary download of the program in your Advantage account.
