How is a vice president decided?

Answer 1

While the office of the vice president is occupied, at election time (in the fall of every leap year and every year ending in "00"), the voting public makes their preferences known by voting for the electors associated with their choice for President and Vice President. Each Presidential candidate runs together on the same ticket with a Vice Presidential candidate, and you vote once for the pair. Each state and D.C. uses the results of the state's "popular vote" to determine which electors will be appointed. The following month, the electors record their votes for President and Vice President. A Vice Presidential candidate must receive the votes of at least 270 of the 538 electors in order to win. If no vice presidential candidate receives at least 270 votes, the U. S. Senate is required to elect the vice president from between the two candidates who received the most electoral votes. The Senate votes until one of the two receives the votes of at least 51 of the 100 Senators.

Whenever the office of the vice president is vacant (usually due to the death or resignation of the President or the Vice President), the President appoints somebody (it could be anybody who is qualified to be President) to be Vice President. Both houses of Congress then vote on the appointment. If a majority of both houses approves the appointment, the person is sworn in as Vice President. If at least one house rejects the appointment, the President chooses somebody else, and the process repeats until Congress approves one of the President's appointments or until the next inauguration day, whichever comes first.

Answer 2

They are chosen by the person who is running for president.