@PopPopBilly2810
there is no penalty to amend a return with Form 1040-X and
submit a corrected/revised Form 8606 for any tax year.
No one to my knowledge has ever posted on the TurboTax forum that they were charged $50 for a late submission of a missing Form 8606.
Use Form 1040-X to add or correct information on an already filed tax return.
The IRS is also pretty clear in the instructions that Form 8606 can be filed by itself only if you are not otherwise required to file a tax return.
If you attach 20nn 8606 to 20nn Form 1040-X you won't have to sign 8606
NOTE: if no dollar amounts are changing, you should leave lines 1-23 on Form 1040-X EMPTY.
