To avoid underpayment penalty in 2025 you need to have paid via withholding or timely (quarterly) estimated taxes (ES) "as you go" thru the year, either: 100% of your 2024 tax (110% if your AGI > 150k), or 90% of your 2025 tax, whichever is smaller.
By default TT will generate ES vouchers based on the first option, paying 100/110% of your 2024 tax, and assumes your 2025 withholding will be the same as 2024.
One possibility if you had a refund in 2024 and don't normally pay ES, is your AGI is over 150k so by default TT is determining you need to pay 110% of that in 2025, and your withholding is not enough to meet that even tho you had a refund in 2024. But if your 2025 situation is the same as 2024 then you only need to pay 90% of that thru withholding by 12/31 (and the balance by filing deadline 4/15/26), which could be a big difference and the default estimates are too high. But that's just a guess, it depends on your situation. It's worth understanding why these were generated and any implications for your withholding or ES required for 2025.
Under "Other Tax Situations" / "Form W4 and Estimated Taxes" you can work through planning/estimates for 2025.
