Of course this deduction is only useful if your total itemized deductions are greater than the standard deduction, which is probably not the case for most people.
Normally this would be reported in box 10 of a Schedule K-1 (Form 1041) that you received from the estate and entering the Schedule K-1 would cause TurboTax to automatically put the amount on line 16 of Schedule A (there is no longer a line 27 on Schedule A, that line disappeared in 2018). If it's not reported on a Schedule K-1 (I'm not sure why it wouldn't be), you can enter it under Deductions & Credits -> Other Deductions and Credits -> Other Deductible Expenses in the box for Estate tax deduction no reported on an estate K-1.
