What is a leap year? And how was it formed

A leap year is a year that has 366 days, where February is 29 days instead of 28 days; however, the earth's orbit entirely around the planet in 365.2422 days, not 365, but it does not make sense to include a quarter of a day in the year, so that is why the standard year is 365 and 1 year has got an extra day adding up all those quarters.