If TurboTax "thinks" your original return was prepared as marred fling jointly --it is because you are making another user error. You have to work from the original tax return EXACTLY as it was before you filed it the first time. (and why did you say you were single if you were married...?) . If you messed with that original tax return at all-- before you began the process to prepare the Form 1040X, then you need to put it back to exactly the way it was before you began to amend.
The mistake you made might even need the help of a tax pro if you are unable to fix it yourself.
See if you can "un-do" amending and start over -- check to see what the filing status says on the Form 1040 before you start the amended return.
I clicked on “amend” by mistake
Do you now understand that all the income from BOTH spouses goes on the same tax return? Your information, your income, your spouse's information and your spouse's income all go on that same amended return in order to correct the mistake that was made when you filed incorrectly as Single.
Ok ... if you are switching filing status from Single to MFJ then it can be complicated especially if the other spouse had also filed incorrectly. Once both original returns have been fully processed you can choose which one of the filed returns you will amend to add all the other spouse's information ... only amend ONE return.
Some entries will either need to be made on the paper form you will have to mail in or in the FORMS mode in the downloaded version. So choose the downloaded option to amend the return. Changing the filing status means you will NOT be allowed to efile the amended return.
Now if you have started the amended program AFTER you made changes you MUST undo those changes and start over again.
Look at the form 1040X …
Column A should have the figures from the original return, Column C the corrected figures and Column B the differences between the other 2 which needs an explanation on page 2 of the form 1040X.
If you completed it correctly you will see an entry on either line 16 OR 18:
On line 16 should be the amount you paid with your original return. If you paid nothing already then this line should be zero.
On line 18 should be the amount of your original refund you received. If you have not received your refund yet then you need to wait for it. If the refund changes from what you expected then this line must reflect that change.
Then you will see your extra refund on line 22 OR the new balance due you need to pay on line 20.