A written constitution is the one in which a document or a collection of documents contains the fundamental rules regarding the main organs and institutions of government. It is deliberately formulated and is consciously planned. It is formulated by conventions or constituent assembly. The constitution of India is designed and adopted by the constituent assembly.

An unwritten constitution evolves out of free documentation of rules and regulation. At first the rules are practised and become a part of the constitution. 

For example: constitution of Britain is an unwritten constitution. It is not described through any single document but contains many sources to describe it.

An enacted constitution emerges from deliberate human effort. It is formulated consciously by constituent assembly or by king, or a sovereign authority or Parliament. It is embodied in a document or in series of documents.

An evolved constitution is the one which has emerged over time. The rules have been added whenever need was felt. It is the result of accumulation of material which resulted in shaping the political institution. It is not made but has grown from past and is a collection and continuation of traditions, customs, usage and judicial decisions.