To file as "qualifying widower", you must have a qualifying dependent who is your child or stepchild (not a foster child or other type of dependent) who you can claim as a dependent, or who you could have claimed as a dependent except their income or marital status disqualified them.
Normally, Turbotax will ask you about your marital status and your dependents, and would have offered the qualifying widower status if you qualified. If you do qualify, you can use this status in 2021 even though you skipped 2020. You can also amend your 2020 tax return for 2020 if you qualified but skipped it.
But qualifying widow or widower is not for all taxpayers with deceased spouses, it is only for taxpayers whose spouse is recently deceased AND who have a child dependent.
