from where do the finances come for this organization?
The UN is financed from assessed and voluntary contributions from member states.
United Nations
The UN is financed from assessed and voluntary contributions from member states. 
give the detailed information about the uno before its foundation The UN was formulated and negotiated among the delegations from the Allied Big Four  at the Dumbarton Oaks Conference from 21 September 1944 to 7 October 1944 and they agreed on the aims, structure and functioning of the UN. what are the functions of the united nations? To maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a centre for harmonizing the actions of nations what could be the key reason for the establishment of this organization? To maintain international peace and security where is their headquarters? he UN is headquartered on international territory in New York City, with its other main offices in Geneva, Nairobi, Vienna and The Hague. what is the structure of this organization? The UN system is based on five principal organs: the General Assembly, the Security Council, the Economic and Social Council , the International Court of Justice and the UN Secretariat
wiki:19682859
United Nations [SEP] Funding
The UN budget for 2020 was $3.1 billion, but additional resources are donated by members, such as peacekeeping forces. The UN is financed from assessed and voluntary contributions from member states. The General Assembly approves the regular budget and determines the assessment for each member. This is broadly based on the relative capacity of each country to pay, as measured by its gross national income (GNI), with adjustments for external debt and low per capita income. The Assembly has established the principle that the UN should not be unduly dependent on any one member to finance its operations. Thus, there is a "ceiling" rate, setting the maximum amount that any member can be assessed for the regular budget.