A bureaucratic organisation can operate more or less the same irrespective of the identities of individual workers. As long as there is someone who can fill a particular slot and follow orders, operations will continue. Thus in a bureaucracy the workers are replaceable cogs. No one is essential. Even the top boss can be replaced and things will go on just about the same as before.
Bureaucracies are very common in today's society.
Most government bodies are bureaucracies, including government departments, schools, the military and the police. Most large corporations are run bureaucratically, as are most large churches, political parties and trade unions. This idea of bureaucracy is somewhat different from the everyday picture, which is usually of a government department such as the tax office. Government departments are indeed good examples of bureaucracy, but so are large corporations. The key is the way work is organised.