First, please make sure that you have purchased the right product. The codes for TurboTax Online will not work with TurboTax CD/Download & vice-versa.
If you have bought TurboTax Online, please go to turbotax.ca/activate to use your code before you start your returns. You can see this TurboTax FAQ for step-by-step instructions: In TurboTax Online, how do I use a prepayment code?
If you have bought TurboTax CD/Download, you will be asked for the licence code when you install the software. Please see this TurboTax FAQ for more information on the licence code: Where is my TurboTax licence code? You can download the current version of TurboTax CD/download edition here: Choose the 2021 TurboTax edition you need (for Windows). You can download older versions of TurboTax CD/download edition here: Where can I download the CD/download edition of TurboTax?