The license code in entered in the TurboTax software that you install on a personal computer, not on the TurboTax online editions.
See this TurboTax support FAQ for entering the license code using the TurboTax desktop CD/Download editions - https://ttlc.intuit.com/turbotax-support/en-us/help-article/license-information/install-turbotax-cd-...
