sorry for your loss. if your spouse dies in 2020 you can file a joint return. if your husband died in the previous year and you have no dependents your filing status is single. filing as single with the retirement distributions being taxable (box2a) will result in significantly more taxes. you may need to contact the administrator so withholding on those distributions can begin otherwise you'll have a huge tax bill in 2021 and penalties because you are required to have paid in through withholding or estimated tax payments either 90% of 2021 tax or 100% of 2020 tax (110% if your adjusted gross income for 2020 is more than $150,000)
a distribution is taxable regardless of whether it is an RMD or not.
have you informed the administrator about your husband's death because there should have been an option assuming your husband had started getting required distributions under the plan? You, as beneficiary, are required to take distributions over either your life expectancy or the remaining life expectancy of the deceased, whichever is longer. thus what you received and will receive in the future are RMD.
some states tax retirement distributions others do not.
