Why is a government needed?

Government is necessary to establish and maintain order and social control. At its fundamental level, government is responsible for the safety and welfare of its individuals. As John Locke famously stated, it is necessary to enter into a “social contract," giving up some of our innate rights, for the general welfare and safety of the population at large.
While it has expanded and developed in leaps and bounds, especially in a country as massive as the United States, the government still maintains its fundamental role in society: protect the safety of the citizens and ensure freedom and integrity. This is maintained through business regulations, environmental conservation, foreign policy, regulation of the economy, civil rights, and much more. The government is intended to be the protector of the people.

There are various reasons why we need to have a government. One reason is that a government provides order within a society. Without a government, there might not be laws. People would feel they could do whatever they wanted, whenever they wanted to do these things. We likely would be less safe without laws.
There are various services that government provides that are important to people. Without a police force, it would be harder to deal with illegal activities. In colder climates, roads need to be plowed in the winter. State and local governments set up public schools and public universities. In some places, the government arranges to have garbage collected and materials recycled. The government monitors the activities of businesses to help to ensure that consumers are being treated fairly. The government also provides relief to people when natural disasters, such as tornadoes, hurricanes, and earthquakes, occur.
Conducting relations with other countries would be very difficult if a government didn't exist. The government is responsible for making treaties and, if needed, going to war. The government is responsible for maintaining a military.
Governments take on many roles that help to ensure that society can function smoothly.
https://www.thoughtco.com/why-do-people-need-government-721411