Spouse filed his taxes separately & I haven't filed mine yet for 2019. We would like file jointly now. My return will be more complicated than his, so I am wondering if I need to file my taxes MFS then amend mine and add his information to the amendment or is there another way to do this. I was thinking I could just amend his and add my information but I haven't filed yet and mine is more complicated than his. Any insight is appreciated.
You amend the return already filed and add the spouses data to it.
Amended returns can only be mailed. It is suggested that it be mailed certified with return receipt (or other tracking service) to verify that the IRS receives it.
See this TurboTax FAQ for detailed amend instructions:
-- Amended returns can only be mailed - allow 8-12 weeks - can take up to 16 weeks (4 months) for processing.
You can check the status of the amended return here, but allow 3 weeks after mailing.