I filed jointly from 2016 to 2021. Should I include my ex-husband's name in the form for those years?
yes see line 2a also his Social Security number. note 2016 may not be available any longer.
if you changed your name also sign your current name
The form provides space for only four years. Can I include two forms in one envelope?
to be on the safe side mail separately also mail using a tracking service.
