From the Website of the General Assembly of the United Nations

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. Comprising 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.

It also plays a significant role in the process of standard-setting and the codification of international law. The Assembly meets from September to December each year, and thereafter as required.

Decisions on important questions, such as those on peace and security, admission of new members and budgetary matters, require a two-thirds majority. Decisions on other questions are by simple majority. Each country has one vote. The Assembly has adopted its own rules of procedure and elects its President for each session.

Read more about the functions and powers of the GA