you and your spouse can file a joint return if you were married in 12/31/2023. both must agree to this. if you do a joint return you include her income for the entire year not just since you married. If Dad files a return for her before you file a joint return, you will not be able to e-file.
if you both agree to file jointly, she needs to tell her dad not to file for her. if he already has filed for her
since her return has already been filed, you will need to amend her return to married filing jointly and then add your information to her return. The 1040X for amending 2023 returns will not be available until mid-February. There are instructions on how to amend your return from MFS to MFJ. You should not try to amend her return until it has been fully processed and you have received the refund or her payment has cleared.
Amended returns for 2023 may be -e-filed. be sure to take into account on the amended return the actual refund or payment. If you are due a larger refund than on your original return, your amended return should only show the difference and you will receive a separate check for it. If you owe money on your amended return, it will show only the new amount owed, you will have to mail a check with the return.
