The purpose of a student council is to provide a participatory process and a level of limited self-governance for the students attending an educational institution. Student representative bodies (student councils) usually consist of students only, have a formal management structure (e.g. a board, president or chairperson, secretary, treasurer and other office holders) and a constitution. To become a member of a student council (or equivalent), you have to be eligible for membership (be a current student of the institution/school and sometimes be of a certain age), run as a candidate in the election and get elected. Some institutions do not run elections and instead either appoint people to the student council, or in the case of small schools, any student can become a member without having to be elected or appointed.
Student councils typically have limited powers to represent the students before the school management, education authorities, local politicians and umbrella organisations. They usually have an advisory function and their primary role is to make proposals to the principal or school management in matters concerning student wellbeing and school operations. These matters can range anywhere from the curriculum, extracurricular activities to youth work and other school services (organising festivals and other events at school).
Whereas in most cases, student councils serve the purpose of catering to the needs of the student body (through consultations, surveys, social actions and campaigns) and voicing their concerns in dealings with adults (such as teachers, principal and the school board). In some cases, student councils can also have certain rights given to them either by their constitution or in some countries, by legislation. In these cases, student councils can act independently, without seeking approval from the principal.