The new 72 year old rule. Temporarily go in and change her age to 72. Continue through the 1099R screens to the Uncommon situations and the QCD will be there. Once you completed the QCD screens, go back the My Info and change her age back to her correct age.
For those with a birthdate between July 1, 1949 and June 30, 1950, 2020 TurboTax presently (now version R16) has a bug the prevents it from asking the necessary question regard transfer of the distribution to charity. As a workaround for this, with the CD/download version you can provide the QCD-amount information on the 1099-R in forms mode or in any version of TurboTax you can temporarily change your birthdate in TurboTax to something before July 1, 1949, edit the 1099-R form in TurboTax and answer the question asking how much was transferred to charity, then change your birthdate back in TurboTax back to your actual birthdate.
Inappropriately tied in the TurboTax logic, not tied in the tax code. Yes, this is obviously how this bug came to be in TurboTax. The developers didn't design the change in TurboTax behavior appropriately.