An unfounded claim, describing the democratic process of electing Joe Biden for President as a “coup”.
This is part of a recurring disinformation narrative about the US in the context of the US presidential election. In its interim assessment on the conduct of the election, the OSCE finds that the contest was:
"competitive and well managed" (p. 1), noting that "evidence-deficient claims about election fraud" (ibid.) have been refuted by "election officials at all levels" (p. 3) and "national security agencies" (p. 11).
There were extensive investigations about possible fraud, which turned out to be unfounded. This unprecedented scrutiny led to the conclusion that the November 3rd elections were the most secure elections in the history of the United States.
Allegations of electoral fraud have been dismissed more than 60 times by different US courts and judges, both Republican and Democrats, due to lack of any significant evidence, including the Supreme Court in two occasions.
You can see other examples of this disinformation narrative, such as Dominion deleted 2.7 million Trump votes nationwide, Voting systems were designed to be hacked and were used by Biden to win the election, Massive fraud in the US 2020 Presidential elections.
6 January 2021, during a debate in the Senate, a number of Trump supporters broke through security perimeters and violently entered the Capitol, the seat of the US parliament, the Congress. The aim of the protesters was to impede the process of formally installing Joe Biden as the President of the United States, despite Biden winning the November election. An overview of the incident can be found here.