They are organizations that want to form government through elections using legitimate means. They are formed with the intention of getting political power and using that to do things that are of special interest to them. Political parties have some ideas about how the society should be. They represent the interests of different groups. Different groups also try to influence political parties. When some groups feel that their interests are not served, they form new parties. Or they work as pressure groups and try to influence the government. Some political organizations try to get power but they do not get it. Such organizations can be seen only as certain institutions.
Max Weber says that Caste is concerned with economic matters, communal organizations worry about social matters and political parties think about getting power (authority). Each party has certain aims. It will try all it can to achieve these aims.
Not every organization has the power to influence government. It is the strong sections of the society that exert pressure on the rulers. These sections form organizations based on caste, race, and gender. They influence government. Social organizations and interest groups play a big role in democracy.