TT is going to determine the safe harbor amount which is 100% of your 2024 tax (110% if AGI > 150k) or 90% of your estimated 2025 tax, whichever is smaller. By default if you don't provide info on 2025 income, it will use 100/110% of your 2024 tax, and assume your 2025 withholding is the same as 2024, and apply both of these evenly and quarterly, and if the withholding exceeds the safe harbor amount then you will not have any estimated tax. Did you have a high withholding for 2024 and a refund? I'm guessing that's why it thinks you don't need to pay ES for 2025. If it's material you may be able to reduce withholding and earn interest on that money.
To adopt the 2025 method you can go thru the interview under "Other Tax Situations" / "W-4 and Estimated Taxes" and provide information for 2025.
If you are on TT desktop you can go into Forms mode and look at "Est Tax Options" to see the calculation. Not sure equivalent of that for TT online, either way try the interview questions.
