To enter your RMD and withholding information, just enter your Form 1099-R into TurboTax. See the TurboTax Help article Where do I enter my 1099-R? for guidance.
You’ll be given the opportunity to enter all the relevant information on your 1099-R.
You receive, and need to report, a Form 1099-R when you receive $10 or more from a retirement plan.