How can I update my 2020 tax payment?

[xmasbaby0]

Could you please be more specific?  What exactly are you trying to update?   And for what payment for 2020?   

[Critter-3]

If you had a balance due on the 2020 return then that is what the return will say forever ... payments you made after you filed will not be shown on a form 1040 and there is no way to "update" that in the TT program.    If you went to a paid tax pro and walked out of the office with a paper copy of the return showing a balance due  then it would always show a balance due ... the paper would not magically change just because you paid the balance due off with the IRS.   If someone is requiring that you show proof of payment then show them the bank/cc receipts  and/or  get your account transcript from the IRS.   https://www.irs.gov/individuals/get-transcript