As of February 2021, we currently only offer TurboTax CD/Download for Windows for 2015 to 2020. For TurboTax Online we only have 2018, 2019 and 2020.
This page will show you what we have available for 2015 to 2019: https://turbotax.intuit.ca/tax-software/prior-year-taxes.jsp
FYI: For most of those years, you will need to print and mail your returns, as the CRA only accepts the last four years with their NETFILE service.
If you need to prepare returns for years prior to 2015, the CRA has tax return packages going back to 1985: https://www.canada.ca/en/revenue-agency/services/forms-publications/tax-packages-years.html