“The U.S. presidential election cycle is split into two voting phases. First is the voting for the nomination in primary elections and caucuses, which takes place on different days in different states. Then comes the general election, which takes place on Election Day everywhere in the country.”
The Primary Election is where the political parties hold an election for registered voters to exercise their right to choose which candidate they want to compete against the candidate of the opposing party for the political office being sought. Many candidates can compete in the primary election, but only one candidate comes out victorious to go on to compete in the General Election.
Think of the primary election as the means to determine the party's one official presidential candidate or senate candidate or representative or governor to be on the ballot in the final step of the election process, the General Election, which is always the Tuesday following the first Monday in November.
A midterm election is held two years after the presidential election. Think of it as the election half way through the President’s four-year term. Up for reconsideration by the voters during the midterm election are all 435 members in the House of Representatives, and some members of the Senate.
"Presidential primary elections or caucuses are held in each U.S. state and territory as part of the nominating process of U.S. presidential elections. Some states only hold primary elections, some only hold caucuses, and others use a combination of both. The primaries and caucuses are staggered between January and June before the general election in November."
“The primary elections are run by state and local governments, while caucuses are private events that are directly run by the political parties themselves.
"State governments fund and run primary elections in much the same way they do the general election in the fall. Voters go to a polling place, vote and leave.
"At a caucus, individuals who are viewed favorably within the party are identified as potential delegates. After a comprehensive discussion and debate, an informal vote is held to determine which individuals will serve as delegates at the national party convention.”
"The four most common types of primary elections are open, closed, semi-open and semi-closed. Each state must decide which type it wants to adopt.
The President must:
“Any person who meets these requirements can declare his or her candidacy for President at any time. Candidates must register with the Federal Election Commission (FEC) once they receive contributions or make expenditures in excess of $5,000. Within 15 days of reaching that $5,000 threshold, candidates must file a Statement of Candidacy with the FEC authorizing a principal campaign committee to raise and spend funds on their behalf.” https://www.usa.gov/election