Established in 1945 under the Charter of the United Nations, the General Assembly occupies a central position as the chief deliberative, policymaking and representative organ of the United Nations. Comprised of all 193 Members of the United Nations, it provides a unique forum for multilateral discussion of the full spectrum of international issues covered by the Charter.
The Assembly meets from September to December each year (main part), and thereafter, from January to September (resumed part), as required, including to take up outstanding reports from the Fourth and Fifth Committees.
Each of the 193 Member States in the Assembly has one vote. Votes taken on designated important issues require a two-thirds majority of Member States, but other questions are decided by a simple majority.
The Assembly allocates to its six Main Committees items relevant to their work. The six Main Committees are: the Disarmament and International Security Committee (First Committee); the Economic and Financial Committee (Second Committee); the Social, Humanitarian and Cultural Committee (Third Committee); the Special Political and Decolonization Committee (Fourth Committee); the Administrative and Budgetary Committee (Fifth Committee); and the Legal Committee (Sixth Committee).
Source: https://www.un.org/en/ga/about/background.shtml for more information.