Non-governmental organizations (NGOs) are non-profit, voluntary, and private groups operating independently of government control to address social, political, or environmental issues. Founded by citizens, they range from local to international, focusing on advocacy, service provision, and humanitarian aid, often funded by donations or grants. 

Key Aspects of NGOs:

• Independence: They are not part of any government, though they may receive government funding.
• Purpose: They focus on public interest goals, such as human rights, health, education, or disaster relief.
• Structure: They can be organized as associations, charities, or foundations.
• Operations: They operate at local, national, or international levels. Wikipedia +3

Types and Roles:

• Advocacy: Actively lobbying and advocating for specific policies.
• Operational: Implementing projects to achieve specific goals, such as providing medical services or aid. 

Examples:

• BRAC (largest NGO)
• World Economic Forum
• Alzheimer Europe, Autism-Europe, and other specialized groups
• Dobrudja+, International Research & Innovation Center 

The term was first used in the United Nations Charter in 1945, and there are currently over 12 million NGOs worldwide.