In order to get on the ballot, a candidate for president of the United States must meet a variety of complex, state-specific filing requirements and deadlines. These regulations, known as ballot access laws, determine whether a candidate or party will appear on an election ballot. These laws are set at the state level. A presidential candidate must prepare to meet ballot access requirements well in advance of primaries, caucuses, and the general election.

There are three basic methods by which an individual may become a candidate for president of the United States:

1 - An individual can seek the nomination of a political party. Presidential nominees are selected by delegates at national nominating conventions. Individual states conduct caucuses or primary elections to determine which delegates will be sent to the national convention.

2 - An individual can run as an independent. Independent presidential candidates typically must petition each state to have their names printed on the general election ballot.

3 - An individual can run as a write-in candidate.

Requirements for Independents
Generally speaking, an independent presidential candidate must petition for placement on the general election ballot in all 50 states as well as Washington, D.C. A handful of states may allow an independent candidate to pay a filing fee in lieu of submitting a petition. The methods for calculating how many signatures are required vary from state to state, as do the actual signature requirements. For instance, some states establish a flat signature requirement. Other states calculate signature requirements as percentages of voter registration or votes cast for a given office.

Information from Ballotpedia.com

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