if you haven't been paying quarterly estimated taxes (see response from @guywong who lays out the details) you can stop the penalty due from Q1-2 accruing further (at 8% annual rate) by paying those portions ASAP, and then pay the quarterly estimated tax for Q3 in Sep, Q4 in Jan. If your income was uneven and in particular skewed to later in the year (e.g. Roth conversion or large cap gain in Q4) you may be able to pay the ES unevenly to line up with the income and then file Form 2210 Annualized Income method but you will need to calculate your AGI, withholding, qualified dividends, LTCG etc thru 3/31, 5/31, 8/31.
TT generates ES vouchers by default for the following year when you file, based on paying 100/110% of your prior year tax and assuming your 2025 withholding is the same as 2024, but you can also work through an estimate for the following year under Other Tax Situations / Form Q4 and Estimated Taxes to see if paying ES based on 90% of current year is better.
If able, pay ES online at irs.gov don't bother with vouchers and checks.
