Thanks for your time in developing that answer and especially the detail on completing the 1041-A in the software, that will be helpful, even if I have to print it anyway.
My desire to e-file was kind of naive, hoping for "closure" much sooner. The IRS is taking pretty long these days to process paper returns (though maybe they're faster with the 1041s?)
Here's another naive thought I had. Since I have to file a paper 1041 and 1041-A , why not write a one line message at the top of the 1041 to the effect of: "See SSN xxx-xx-xxxx for income reporting prior to mm/dd/2021". I'm innocently (and maybe unnecessarily) trying to be helpful to the IRS if they need to verify that income reporting occurred for these same investment assets on my mom's individual tax return for that part of 2021 up until the day she passed. I'll be filing that tax return also with TurboTax and I believe, if it's like last year (me filing for a deceased taxpayer), that TurboTax will make me print that one and mail it as well.
