I didn't fill the form 8606 for 2022 tax return about my backdoor Roth conversion. How can I amend my 2022 tax return in Turbotax by filling out the form 8606?

[Anonymous_]

@dmertz?

[fanfare]

The proper way to file Form 8606 is attached to Form 1040-X.
Form 8606 can be mailed by itself only when you are otherwise not required to file a tax return.

Did you do a true backdoor contribution that is tax-free?
In that case Form 8606 will show a taxable amount of zero.
Do you have the correct taxable amount on Form 1040 Line 4b and did not take a deduction? (Schedule 1 Line 20)?
If that is all true then only Form 8606 has to be attached.
After you e-File,
get Form 1040-X from IRS website and mail it in with your 8606, which you can also get in fillable PDF.
Note: when you are not changing any dollar amounts on your amended tax return, you can leave all the lines 1-23 EMPTY.

Part III explanation: "didn't include Form 8606 with e-File".
You will have to mail it so this does not use up your one 1040-X e-File.
Done this way, you sign 1040-X, not 8606

@carpinheiro