1099-r 3-year tax payment for distribution of early retirement due to covid. (CARES)

Since the form is not available yet no one knows.

Did the client repay some of it?

"Box 4 - Federal income tax withheld (I paid the 10% penalty upfront)"

No; you prepared to need to pay some taxes on this distribution for how it applies to your entire 2020 tax year. What you paid is the same as an Estimated payment or a Withholding payment. You paid in advance of something yet to be determined.

There is a required withholding on distributions in some situations, anyway. It still isn't your Tax.

"If I decide to use it on my 20, 21, and 22 tax returns, how exactly do I use it?"

You are not "using" it across years. It is paid into the IRS and will be applied to what you owe for 2020 from the 1040. Not for any one thing only.

If you qualify and if that distribution qualifies, you can treat it as a covid-related disaster distribution. The treatment for Disaster means the taxable Income can be split across three years of tax returns. That spreads the impact of this additional income across three years of tax filings. But, for instance, if 2020 was a low income year, and you know 2021 and 2022 resume a much higher financial picture, you might not want to spread it out at all.

And if it qualifies as disaster related, there is no 10% penalty on that distribution.

Something tells me you are lost on the internet and trying to do you own taxes. This is where Tax Preparers using ProSeries programs would be posting their questions. Are you using ProSeries to prepare a client's tax return?