After Senator Warren went on TV and said Elon Musk paid $0 in taxes in 2018, he responded in a Tweet dated 20 Feb 2022 saying (emphasis added):
Will visit IRS next time I’m in DC just to say hi, since I paid the most taxes ever in history for an individual last year. Maybe I can have a cookie or something …
From the context, it is clear both are talking about personal federal income taxes (not sales tax, property tax, state income tax, or taxes on Musk's businesses).
Also, "last year" is ambiguous as depending on how you file, one might pay 2021 taxes throughout 2021, all in 2022 when filing, or some of both. And, Warren was talking about 2018 (with the same ambiguity about which year's taxes it was). Regardless, Musk's claim clearly applies to either 2020 or 2021, so answers should look at one of those two years.
Did Elon Musk pay the most income taxes ever for an individual for tax year 2020 or 2021?
I'm skeptical that the IRS even publishes enough information for someone to know how their own tax bill compares to that of others.