Question

why different types of codes are there for different types of villages, districts ,mandale etc???

Answer 1

because everything having there place like village is a Smallest unit of society where is district is a biggest unit of society .and sometimes the name of cities and cities and villages should same as others o village and cities. like in your class two girls having same name so they identify in exam according to their roll number like and everything is
particular code or number .

Answer 2

this is because our India is very huge in which so many villages,cities are there but many of the cities have common name this create so much confusion
codes are also used for official work which make our work easy.