Form 2210 is only generated if one of the exceptions in Part II applies, when filing if you go thru Other Tax Situations > Underpayment Penalty that's where that happens otherwise you would file with the penalty on Line 38 of Form 1040 and no Form 2210 is filed. IRS recalculates it independently based on information in their system - differences in prior year AGI or Estimated Tax payments for example could then trigger a different penalty result.
For line 8 follow the instructions for Form 2210 or provide more details here if still stuck and someone may be able to help further. But for most people it's 100% of their 2024 tax liability (generally line 22 on Form 1040 for most people, but follow instructions if you had stuff on Schedule 2 or refundable tax credits), or 110% of that amount if your 2024 AGI was > 150k or 75k if married filing separately.
If you are using TT desktop you can go back to your return and in Forms mode double click on Line 38 then again in the 1040 worksheet and it will show Form 2210 generated by Turbo that did not need to be filed. But that may not have the correct info if IRS determined you owe a different penalty amount. You can also check your transcript and payment details under your account at irs.gov to see why there may have been a difference in the calculations.
