The Basic definition of urbanization is as follows:
"Urbanization is defined as a process of people moving into cities and surrounding areas from the more rural areas" ( dictionary.com). / Increase in the number of urban population. As evident from the definition urbanization doesnot mean the conversion of villages into cities.
Urbanization is also defined by the United Nations as movement of people from rural to urban areas with population growth equating to urban migration.
Urbanization is migration, more specifically Migration of rural population to the cities. (migration could be in both directions, but when it is towards the urban areas the process is called urbanization).
Thus in my opinion when the checker asked to describe in detail the urbanization process, he meant to explain and define in detail the urbanization process, explain why the trend of urbanization is increasing, what are the disadvantages of urbanization if not properly controlled.