You are not giving us enough information to answer your question properly.
If you have purchased the online version, you might be asking about the activation code which is an eleven digit code you have received you have purchased the product. You will need to apply the code prior to filing the return.
If you have purchased one of the desktop packages, then it will be a 21 registration key you apply when you download TurboTax.
If you are filing a business return and are filing a T2125 form, then you might need to find the industry code for your business which can be found at:
https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/t4002/t4002-13.html
If you need further help, you can contact us via Facebook or Twitter to exchange private information:
https://support.turbotax.intuit.ca/contact/
I hope this was helpful