Thank you for your question. Before you can access Autofil, you need to be registered with "My account" at the CRA.
Withing the TurboTax product, Autofil is located at the very beginning of the Income section. With TurboTax free it is at the Your taxes section. https://turbotax.community.intuit.ca/questions/1299375-i-used-turbotax-to-do-my-taxes-last-year-and-...
I hope this helps.