This credit is covered during your state tax interview. For example, the New York Property Tax Relief or STAR Credit is listed under Take a look at New York credits and taxes. (Click the first screenshot below for reference.) Clicking the Learn More link provides additional information about the credit.
Note: To get to the state interview in TurboTax Online, click the State tab at the left side of your screen. (Click the second screenshot below.) Follow the onscreen instructions to add the state tax return. If your state has a Property Tax Relief Credit, it will come up at some point during the interview.