June 4, 2019 12:38 PM
TurboTax calculates a 'base estimate' for your sales tax deduction based on your address and income. To that estimate, you can add sales tax paid on 'large purchases' (vehicles/building materials).
TurboTax asks you if you want to use the estimated sales taxes paid OR would you rather enter all of your purchases/receipts manually. Most people use the estimate and add sales tax on larger purchases.