They are nominated by a vote of the delegates at the respective party nominating conventions. Some of the delegates are bound to vote in accordance with the results of an earlier state primary election or caucus.
Picked individually by the candidates for president
Candidates for President get to choose their own running mates.
Candidates for president and vice-president run as a team- they are elected as a team by the voters through an indirect process spelled out in the US Constitution. A body known as the electoral college officially elects the president and vice-president but the voters choose the electors based on the candidates they promise to vote for.
each party nominated presidential and vice-presidential candidates
2 candidates * 5 vice-president candidates = 10 combinations.
During the national convention
Officially, the parties still select the Vice Presidential candidates. Unofficially, each Presidential candidate chooses his/her own running mate.
Usually they are senators or governors who are often nominated. The Vice President is 99% nominated with no doubt, except if they don't want to.
Each party's Presidential nominee (or incumbent) selects a running mate for an election. If a Vice President leaves office, the sitting President can nominate a replacement to be confirmed by the Congress.
To nominate candidates.
The presidential candidates were president Ronald Reagan and former vice president Walter Mondale.The vice presidential candidates were vice president George H.W.Bush and representative Geraldline Ferraro
The Vice President could become Acting President in the event of Presidential disability, and there is no codified term. A new Vice President would not be nominated. Should the Vice President succeed to the Presidency, then he would serve out the remainder of that President's term, and a new Vice President would ordinarily be nominated to fill the Vice President's unexpired term.