No, you must not modify the details of the Form 1099-R. If you were over age 70½ and the Form 1099-R has a code 7 in box 7 with the IRA/SEP/SIMPLE box marked, TurboTax will ask if you had any of the money transferred to charity. Enter the dollar amount and TurboTax will exclude this amount from the amount it would otherwise show on Form 1040 line 4b. TurboTax will also include the notation "QCD" next to line 4b.
There is no need to include the documentation showing receipt of the contribution by the charity. Just keep it with your tax records.
