The primary election process ends with the national conventions of the political parties. Once the national conventions have been held, and the candidates from the political parties have been nominated and chosen, the presidential election begins in earnest as a contest between the candidates from the political parties.
Some people choose to run for President without being affiliated with a political party. Such independent candidates do not need the nomination of a political party, but they must meet other requirements. For example, independent candidates are required to collect a large number of signatures to support their nominations and typically submit a qualifying petition.
The candidates campaign right up until Election Day, when the Nation finally votes for its President. The candidates travel throughout the country, making public appearances and giving speeches. The parties and the candidates use advertising, direct mailings, telephone campaigns, social media, and other means to persuade the voters to choose one candidate over the other(s). Often, these measures also serve to point out the weaknesses of the candidates from the other parties involved in the general election.
In this national Presidential election, every citizen of legal age (who has taken the steps necessary in his/her state to meet the voting requirements, such as registering to vote) has an opportunity to vote. However, the President is not chosen by direct popular vote. The Constitution requires that a process known as the Electoral College ultimately decides who will win the general election.