I forgot to add a car purchase in the Major Life Changes section, can't figure out how to go back to it. Haven't finished filing yet. Is it too late to change?

[xmasbaby0]

You do not have to go back to those questions.  They have no effect on your tax return.  They only help to lead you to certain interview screens sometimes.   What do you want to enter about a car?  Are you self-employed--using the car for business?

Or did you buy a car for personal use and want to enter the sales tax because you are itemizing deductions?

You are posting your question from the Free Edition, which does not support self-employment income or itemized deductions.

[ErnieS0]

If you purchased a car, you may be able to claim an additional sales tax deduction or use mileage as a write-off, but you’ll have to upgrade to higher versions of TurboTax, as @xmasbaby0 said.

Self-employed

If you used a car for business, you would be asked to upgrade when you added a 1099-NEC or self-employed income. You can add vehicle expenses when you add other business expenses.

Sales tax

Generally, adding a car to your sales tax deduction will not be helpful unless if you live in a state without an income tax, because the IRS allows you to claim either sales tax or income tax, and the income tax deduction is usually higher. TurboTax does the math for you.

If you are able deductions such as home mortgage interest and property taxes and you upgraded to itemized deductions, you can enter your car sales tax in the sale tax section.

1. Type sales tax in Search (the magnifying glass) in the top right
2. Select Jump to sales tax
3. On Let’s Compare Your Sales Tax and Income Tax, select Try Sales Tax Deduction Anyway
4. On "How do you want to enter your sales tax info? select EasyGuide
5. On Major Purchases, say YES to "Did you buy any major items while living in [your state]?
6. On Enter Major Purchases, fill in your vehicle info