Basically, political parties fill political offices and exercise political power. Some of the major functions of political parties are:
Parties contest elections. In most democracies, elections are fought mainly among the candidates put up by the political parties.
Parties put forward different policies and programmes and voters choose from them. There may be different opinions but in democracy, a large number of similar views are grouped together to provide a direction in which policies can be formed.
Parties play a decisive role in making laws. As most of the members belong to a party, they go by the direction of party leadership, irrespective of their personal opinion.
Parties form and run governments. Parties recruit leaders, train them and make them ministers to run the government.
Parties try to persuade people why their policies are better than others.
Final Answer:
Some series of functions performed by political parties are parties contesting elections, they put forward different policies and programs, parties playing a decisive role in making laws, Parties forming and running governments and parties shape public opinion by highlighting their issues.