You now need to create or log into an Intuit Account to use the Desktop program.
Since you now have to log into an Intuit Account when you first install it, all your downloads and licenses are listed there (even if you bought it from somewhere else) so if you need to install it again or install on another computer, even on the other operating system (Windows, Mac) you can download it again.
See this FAQ on How to get started with Desktop. Scroll down to - You need an Intuit Account to use TurboTax Desktop for a few reasons:
https://ttlc.intuit.com/turbotax-support/en-us/help-article/license-information/install-turbotax-cd-...
