Each tax year is separate. You cannot combine them in any way.
You cannot change the tax year. The current online program is for 2024 only. Only a 2024 return can be prepared online and only a 2024 return can be e-filed.
Online preparation and e-filing for 2021, 2022, and 2023 is permanently closed.
Note: The desktop software you need to prepare the prior year return must be installed/downloaded to a full PC or Mac. It cannot be used on a mobile device.
To file a return for a prior tax year
If you need to prepare a return for 2021, 2022, or 2023 you can purchase and download desktop software to do it, then print, sign, and mail the return(s)
https://turbotax.intuit.com/personal-taxes/past-years-products/
You may also want to explore purchasing the software from various retailers such as Amazon, Costco, Best Buy, Walmart, Sam’s, etc.
Remember to prepare your state return as well—if you live in a state that has a state income tax.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.
Yes, you have to do last year's taxes separately from this year's taxes. I would file your 2024 first because you may be able to get it in before the due date, saving you any penalties and interest.
Then tackle 2023. There will be failure to file and failure to pay tax (if you owe taxes) penalties. You should complete them as soon as possible to avoid any additional penalties and interest.
You can prepare your 2023 taxes in the TurboTax Desktop program for 2023. You will have to mail in your tax return(s).
As Xmasbaby0 mentions above, state tax returns will be due as well, depending on your state.
Click here for File your 2023 taxes