If you didn't use TurboTax last year, then you will have to manually add this information.
Easiest way to get to this section is to -
- Log into your account
- Click Take Me to My return (you must click this first before searching)
- Click the search icon in the top right hand corner (magnifying glass)
- Search for "capital loss carryover" and click the "jump to" link
- You will get the series of screens below (see attached screenshots) where you can enter your known amounts
- If you don't know your amounts, then use the other option and TurboTax will help you figure them out - you will need your prior year Schedule D and Form 1040.
Alternatively to the search method, you can get to the same section by clicking the tabs Federal tax -> Wages and Income -> Investment Income (you may need to click "Check for More" or "Show All" to get full list of income items to appear) -> Capital Loss Carryover (see last screenshot)