Im 54 on disability. I lived in MD in ‘21 but now live in TN. Filed 0 in ‘21. What state do I fallen and do I just amend do the 1040 X?

Please clarify your question by providing some additional information so we may better help you. Such as: Are you filing a Tax return for 2024? Did you already file it? Has it already fully processed? Why are you amending your return? Did you live in Tennessee the entire year of 2024? Did you earn money in any other state other than Tennessee in 2024? Did you already file your state tax return? Are you trying to amend your state or federal tax return?

Wild guess here---are you amending your 2021 tax return to seek the third stimulus payment as a recovery rebate credit?    If that is what you are doing----first check to make sure that you did not receive it when they sent them out a few years ago, because you cannot get it twice.

https://www.irs.gov/payments/your-online-account

If you are amending 2021 because you were eligible for the stimulus and are trying to get it now, you have to mail an amended 2021 return by April 15, 2025.   Use the address you want the IRS to use if they need to mail you a letter or a check.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US?uid=m76mq6z2 

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