I am a U.S. citizen. I married my wife in 2023 who lives overseas and currently have a pending immigration application (never lived in or entered the States). For 2023, i tried filing MFJ but this was not possible without my wife obtaining an ITIN so i opted to file MFS with NRA under spouses ITIN/SSN. I dropped off my Federal and State taxes by certified mail today (April 15, 2024). My question is, should I apply for an ITIN (Form w7) for my wife? If i receive an ITIN for my wife, am i able to amend my 2023 return from MFS to MFJ and if so, will the IRS send me the difference in refund?
