Deductions & credits

There is no way to add that now if you have just filed. You need to wait and see if your return is accepted and amend your return if you need to add the charitable donation.

Please see this TurboTax Help article Do I Need to Amend?

The charitable contributions may not make a difference in your tax return. If you are taking the standard deduction on your tax return as most people do, the additional deduction may not matter. If you itemized your deductions and included mortgage interest and real estate taxes, then the charitable deductions may make a difference in your refund.

You should look at the tax return that was just filed to see if you used the standard deduction on the 1040, or itemized on Schedule A. If you were able to itemize, then you can amend to add the additional deduction.