since you prepared it with a desktop version, the only copy existed on that computer unless you made a backup elsewhere. Turbotax does not have copies of returns prepared with any of the desktop apps. even if done online, Turbotax would no longer have the 2015 return.
And...even if you have a copy of your 2015 tax return, that would not prove that you paid the state. Your only proof that you paid your state tax due would be your own bank or credit card records. So you need to dig into your own financial records to find some proof that you paid the state of IL.
@Debi Welliver The IRS is also 7 years. See form 4506 line 6.
But you can try. How to Access prior year online returns
If you can't get the side menus to open up to access the prior year..... You need to start entering some basic Personal Info in 2022 for the side menu to open up. Just continue a little ways into 2022. I had to go though about 12 screens.
If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online. So you need to make and keep your own backups.
Or request a transcript from the IRS
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