see https://www.irs.gov/faqs/estimated-tax
to avoid penalty you have to pay "as you go" during the year via either withholding or timely (usually quarterly) estimated tax payments, the smaller of either 100% of your 2024 tax (110% if AGI > 150k) or 90% of your 2025 tax - your 'safe harbor' amount. withholding is always considered timely even if it is paid unevenly, if you have W2 income you can increase withholding to meet this safe harbor amount, tho only 6 months of the year remain.
If you filed 2024 using TT it would have generated vouchers by default based on prior year tax and assuming your 2025 withholding is the same as 2024. In Other Tax Situation / Form W4 and Estimated Tax you can provide estimates for 2025, or you can use other tax calculators online; you don't have to use the amounts generated by TT if you have a better estimate.
the annual penalty rate is 8% and calculated quarterly so if you owe estimated tax you can't just pay it all in Q4 for example, even tho you met the 'safe harbor' amount or even if you overpay and have a refund, if you didn't pay estimated tax for Q1, Q2 etc you will get a penalty for those quarters until your estimated tax comes back into balance; if you missed Q1 estimated tax you should pay 50% in Q2 to minimize the penalty from Q1 (it won't eliminate it but will stop it from accruing beyond a few months).
Check the link above for more info, if you have more specifics or questions for your situation maybe folks here can help further here if needed.
