I am sorry to hear of your loss.
When you start the return, TurboTax will ask who you’re preparing the return for. Select Someone else. Then it will ask if you are preparing a married or common law return. Once you’ve answered that question, you’ll then be asked if the person has passed away, and if you answer Yes, you’ll prompted to enter the deceased’s date of death.
Here is a FAQ with more information regarding preparing returns for the deceased: https://turbotax.community.intuit.ca/community/product-information/help/can-i-prepare-a-return-with-...
