I skipped entering the sales tax paid for a car purchase thinking I could enter it later. Can I enter it before filing?

I skipped entering sales tax paid in 2023 for a vehicle purchase. The software won't let me go back and enter it now. How can I enter this information? Also selected itemized deduction so I could enter a few deductions not accounted for. The software also won't let me change this back to standard deduction.  How can I edit these items.