Democracy is a system of government by the whole population or all the eligible members of a state, typically through elected representatives.
Direct democracy is a form of democracy in which people decide (e.g. vote on, form consensus on) policy initiatives directly.
Representative democracy is a variety of democracy founded on the principle of elected officials representing a group of people, as opposed to direct democracy.
Switzerland is a rare example of a country with instruments of direct democracy (at the level of the towns, cantons and federal state). Citizens have more power than in a representative democracy.
Representative democracy is a variety of democracy founded on the principle of elected people representing a group of people. For example, three countries which use representative democracy are the United States of America the United Kingdom and Poland.