I need to file my 2020 return. I have some questions related to the previous year's return.

1. Can I file my fed and state return electronically or do I need to mail it to them?

2. Do I need to file my 2020 return before I file my 2021 return?

3. Why the cost of Turbotax premier is costlier for 2020 than 2021?

Thanks

Avnish