They are asking for pages 1 and 2 of your return. Amounts and dates of all estimated tax payments I made for this tax year (if applicable). Any supporting documents verifying income and withholding. Is that 1040, W2, and 1099?
The letter should tell you exactly what the IRS wants. You have not told us what the letter number is. TurboTax does not get copies of letters sent to you by the IRS. If they want your Form 1040, print it and include it with any W-2's or 1099's that show tax withheld. If you made any estimated payments during 2024, you need to include that information. Your own bank or credit card records will be your proof that you made those payments. If you did make estimated payments, did you enter them when you prepared your tax return?
Did you enter the estimated payments you made into your tax return?
Go to Federal>Deductions and Credits>Estimates and Other Taxes Paid>Other Income Taxes