>>12033687 (PB)
House and Senate staff meet with OFR staff to inspect the Certificates of Vote in late December. If any State’s Certificate fails to reach the President of the Senate, the President of the Senate calls on OFR to deliver duplicate originals in its possession to complete the set held by Congress.
Congress meets in joint session in the House of Representatives on January 6 to count the electoral votes. The Vice President, as President of the Senate, is the presiding officer. Tellers open, present, and record the votes of the States in alphabetical order. The President of the Senate announces the results of the State vote and then calls for any objections. To be recognized, an objection must be submitted in writing and be signed by at least one member of the House and one Senator. If an objection is recognized, the House and Senate withdraw to their respective chambers to consider the merits of any objections, following the process set out in 3 U.S.C. §15. After all the votes are recorded and counted, the President of the Senate declares which persons, if any, have been elected President and Vice President of the United States.
https://www.archives.gov/electoral-college/roles