I completed my Mothers 2020 income tax with Turbotax. She has recently passed . How do I import her 2020 income tax using 2020 software to start her 2021 return.

I am sorry to hear of your loss. You can't use the 2020 software to create a return for 2021. When you do get the 2021 software, you will have the option to transfer in her 2020 return. You can read how in this TurboTax FAQ: How do I print/save a copy of my tax return (Online version)?

This TurboTax FAQ has more information regarding preparing returns for the deceased: Can I prepare a return with TurboTax for someone who has died?