Answer:
Citizenship is a legal status in a political institution such as a city or a state. The relationship between a citizen and the institution that confers this status is formal, and in contemporary liberal-democratic models includes both a set of rights that the citizen possesses by virtue of this relationship, and a set of obligations or duties that they owe to that institution and their fellow citizens in return.
Nationality, on the other hand, denotes where an individual has been born, or holds citizenship with a state. Nationality is obtained through inheritance from his/her parents, which is called a natural phenomenon. On the other hand, an individual becomes a naturalized citizen of a state only when s/he is accepted into that's nations framework, and then legally his/her nationality has changed by international law. Article 15 under Universal Declaration of Human Rights states "Everyone has the right to a nationality". "No one shall be arbitrarily deprived of his nationality nor denied the right to change his nationality".
Essentially, an individual is able to change his/her nationality through nationalization, citizenship by descent or inheritance of nationality from parents. An example of nationality is Italian to a person with Italian roots born in the United States.