I entered widow for filing status, however, the filing status appears as single on the 1040 instead of widow. Why?

[xmasbaby0]

So sorry for your loss.   If your spouse passed away in 2021 then you can file a joint return for 2021.   If your spouse passed away in an earlier tax year, you need to have a qualifying dependent child in order to file as a widow(er).   Did you enter a dependent?

[Critter-3]

Widow is your marital status not a filing status.   You  have the option to file one more joint return if you like in the year of death if the person in charge of the decedent's return agrees to it ... simply enter the spouse's info when asked in the MY INFO tab. 

If this is a tax year following the year of death  you cannot have the filing status of Qualifying Widow  UNLESS  you have a qualifying dependent on your return ... thus  your filing status is simply  Single as the program concluded.