Are you referring to the Virginia Military Subtraction? If so, information on the subtraction may be found here on page 22 of the Virginia 2023 form 760.
Military Benefits Subtraction
For taxable years beginning on and after January 1, 2022, certain military benefits received by an individual age 55 or older may be may be subtracted from Virginia taxable income.
In TurboTax Online, in the Virginia tax return, see the screen Enter Your Military Benefits.