Enter it as an item donation in the Donations to Charity section of TurboTax. The amount of the donation will appear on Schedule A line 12, and TurboTax will ask you for the information needed to fill out Form 8283, which will be included in your tax return.
Donations to charity are an itemized deduction. The donation will not reduce your tax or increase your refund unless your total itemized deductions are more than your standard deduction.