There are several types of constitutions, primarily categorized as written and unwritten. A written constitution is a formal document that outlines the fundamental laws and principles of a state, such as the United States Constitution. In contrast, an unwritten constitution is based on statutes, legal conventions, and judicial decisions, like that of the United Kingdom. Another classification includes rigid and flexible constitutions. A rigid constitution requires a special procedure for amendments, making it difficult to change, while a flexible constitution can be amended through the same process as ordinary laws. Each type serves to establish the framework of governance in different countries.