Retirement tax questions

I converted $55,000 from my rollover ira to a roth ira.  I did not withhold any taxes (typical 20%).   I received a 1099R for $55,000 with no taxes withheld.  Instead, I sent  $12,000 to IRS as federal taxes the same day of the conversion (12/31/20).

Question:  Do I report this payment as additional "Federal Estimated Taxes" which was not planned

or "Other Income Taxes" not withheld on a 1099R?