to avoid a penalty, you need to have paid the smaller of 100% of your 2023 tax liability (110% if AGI > 150k), or 90% of your 2024 tax liability, whichever is smaller (this is the 'safe harbor' amount) on a timely basis either thru withholding or estimated taxes.
if you have a penalty check under Other Tax Situations / Underpayment Penalty to confirm the 2023 information in the calculation and figure out what your 'safe harbor' is and you can determine if you underpaid. This calc happens on Form 2210, if you are on TT Online it may be in the PDF with "all forms and worksheets".
you should look at this for 2025 planning also if you expect similar income for 2025 then you either need to increase withholding to avoid penalty or start paying estimated taxes. TT will default ES vouchers assuming the "100% of 2024" option and assumes your 2025 withholding will be the same as 2024, unless you provide estimates for 2025 under Other Tax Situations / Form W-4 and Estimated Taxes.
