Sorry, Online is only for 2025 now. Online for 2024 and prior is closed now so you can not start a new 2024 or prior return or finish one. You have to do each year separately
How to prepare a prior year return
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-prepare-a-prior-year-tax-return/00/25984
To do a prior year return you have to buy the Desktop program here,
https://turbotax.intuit.com/personal-taxes/past-years-products
You will need Windows 10 or Mac Ventura 13 to install it on.
If you can't install the Desktop program or if you have a simple return and want to file for free, you can fill out the blank IRS forms by hand. Here are some basic forms…..
Here is the IRS 2024 Form 1040
https://www.irs.gov/pub/irs-prior/f1040--2024.pdf
OR if you want bigger type use 1040SR for Seniors,
https://www.irs.gov/pub/irs-prior/f1040s--2024.pdf
And 2024 Instructions
https://www.irs.gov/pub/irs-prior/i1040gi--2024.pdf
Sch 1 : https://www.irs.gov/pub/irs-prior/f1040s1--2024.pdf
Sch 2 : https://www.irs.gov/pub/irs-prior/f1040s2--2024.pdf
Sch 3 : https://www.irs.gov/pub/irs-prior/f1040s3--2024.pdf
Then when you do file 2025 enter 0 for the 2024 AGI since you are filing 2024 late.
You have to print and mail prior year returns. 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 UPS or certified mail so you will know the IRS received the return. Don’t forget state.