This is so full of useful information:

The Survey of the Performance of American Elections (SPAE) provides information about how Americans experience to voting in the most recent federal election. Conducted in every presidential election since 2008, the SPAE is the only national survey of election administration that focuses on the process of voting, and provides insights into the performance of elections in the individual states.

In 2020, 18,200 registered voters responded to the survey, which was administered by YouGov. Two hundred respondents each were interviewed in 40 states plus the District of Columbia. 1000 additional interviews were conducted in the states of Arizona, Florida, Georgia, Iowa, Michigan, Nevada, North Carolina, Ohio, Pennsylvania, and Wisconsin. The 2020 SPAE was supported, in part, through the generosity of the Democracy Fund.

This document provides an initial look into some of the findings from the survey. A more detailed report, along with a release of the data set, will follow in February 2021.