I purchase TurboTax from Costco. where to find the license?
See this TurboTax support FAQ - https://ttlc.intuit.com/turbotax-support/en-us/help-article/product-system-requirements/find-license-code/L4GHDgGpr_US_en_US?uid=m7gevd6j
If you bought it in the store, after you paid did you go to the customer service pickup window and get the actual package with the License Code? You might need to go back with the receipt and cardboard and get it.