See my above response for the 8453-PE, which is the E-file Declaration for Form 1065, Partnerships. It was confusing because many people incorrectly believe the signed form that you attached can be seen in your Federal return. The signed 8453-PE does, in fact, get attached to your return BUT the list of forms, preview, etc. will NOT show the signed form; the signed form should be saved somewhere on your computer where you saved it to upload to TT.
I would hope that it is the same process in Estates for attaching a signed 8453-FE. I will be submitting an estate tax return for the year ending July 31, 2024 in August - September timeframe.
