Amend? Or finish preparing a 2023 return that you did not file last year? What are you trying to do?
I finished filing my 2023, but when I was finishing up my 2024 I noticed that for my HSA contribution I had 0 for this year and I listed an amount for 2023. After further investigation I realized that it should have been 0 since it was the employer's contribution. I didn't quite read the whole thing entirely. I stopped after it said "you or someone on your behalf" but further down it said not to include your employer's contribution. So I attempted to amend, but it doesn't allow me to e-file since it the 2023 filing season ended on October 31, 2024.
You can find the address to mail your federal tax return by looking on the last page of the instructions for Form 1040.
For your state return, you may find the mailing address printed on the tax return, normally near where you sign it. Otherwise, you will have to look up the department of revenue in your state online and find the instructions to their tax return.
Only certain paid tax pros using professional tax software can e-file past year amended returns. You cannot e-file an amended return that you prepared yourself using TurboTax. Your 1040X must be printed, signed and dated in ink, and then you need to mail it in. Use a mailing service like certified mail so you will know the IRS received it, since you will have a long wait for it to be processed.
Do not expect quick results from amending. It can take four months or more for the IRS to process an amended return.
You can watch for information here:
https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1