The Electoral College: A2020 Presidential Election Timeline Updated October 22, 2020
After states have completed their vote counts and gathered the official results, “the U.S. Code (3 U.S.C. §6) requires the state governors to prepare, ‘as soon as practicable,’ documents known as Certificates of Ascertainment of the vote.” “The certificates must list the names of the electors chosen by the voters and the number of votes received in the popular election results, also the names of all losing candidates for elector, and the number of votes they received,” according to the Congressional Research Service. “Certificates of Ascertainment, which are often signed by state governors, must carry the seal of the state. One copy is forwarded to the Archivist of the United States while six duplicates of the Certificate of Ascertainment must be provided to the electors by December 14, the date on which they meet.”
https://crsreports.congress.gov/product/pdf/IF/IF11641