From the Document: "Overall, support for voting by mail is quite high, with 64% of likely voters in our survey supporting making it easier to vote by mail, and only 23% opposing. Similarly, more Americans who say they plan to vote in 2020 support than oppose universal extension of vote by mail. A total of 66% of likely voters report that they would support giving every American the right to vote by mail in November, with 22% opposing."
Report no.7, v.1
Northeastern University; Harvard Medical School; Rutgers University; Shorenstein Center on Media, Politics, and Public Policy; Northwestern University
The State of the Nation, A 50-State COVID-19 Survey: https://covidstates.org/