Get your taxes done using TurboTax

Check your emails there will be an email from "CostcoEDelivery"  at "esd.synnex.com" (removed email format since this site removes it) - subject line is "Your Software Activation Keys"

There is a download link at bottom of the email. The link points to https://www.installturbotax.com/ (not sure why they have used a different domain, which makes it look scammy, over using well known turbotax.com or intuit.com domain names. However it does redirect to https://turbotax.intuit.com/personal-taxes/cd-download/install-turbotax/
From there you can choose the one you purchased and have license key.

Hope this helps.