On your 2020 return,
Check if you have a Schedule 3 line 12e which goes to 1040 line 31. And see instructions for 1040 Schedule 3 line 12e page 104.
https://www.irs.gov/pub/irs-prior/i1040gi--2020.pdf
How to pay the deferred self employment tax
https://www.irs.gov/newsroom/how-self-employed-individuals-and-household-employers-repay-deferred-so...
