There are two types of democracy direct and representative. Who are involved you ask? In direct the people of a city/state vote at a "assembly and they voted on war,laws,and leaders" as stated in the rise of democracy video.
A representative democracy is where you have a few people represent a city/state and vote for a large amount of people .
Representative democracy started in 508 BC and representative democracy was used for the United States when the Declaration of Independence was made in 1776, and is used today in Canada and the United Kingdom also.
Direct democracy started in Athens 500 BC
Representative is better because in direct you can vote for anyone this means somebody who doesn't know how lead could be in charge, but the representatives are trusted and voted in to make the right choice.
Direct democracy "was a way for people to govern themselves" also stated in the rise of democracy video