If you want to apply a loss from the current tax year to prior years using TurboTax Online, use the “Find” tool to search for “loss”. Select “Losses” from the list and then click the “Go” button. Check off “Request for Loss Carryback” at the bottom of the “Your Losses Profile for 2020” and click “Continue” until you get to the Loss Carryback page that applies to you.