In Italian, as well as in English, we have two kinds of articles, more specifically definite and indefinite articles. Yet, the main difference between the two languages lies in the number of articles available, a thing that could appear confusing or slightly complicated to the English learner.
In Italian we have the following definite articles: il, lo (masculine singular), la (feminine singular), i, gli (masculine plural), le (feminine plural). The indefinite one, instead, are: un, uno (masculine singular), una (feminine singular). As the indefinite articles do not present a plural form, we can use the partitive article (usually considered a "third" kind of article) when indicating an imprecise quantity of things, people, animals, etc. Its forms are: del, dello (masculine singular), della (feminine singular), dei, degli (masculine plural), delle (feminine plural).