Suppose you are writing an article, essay, report on a topic. Now citations are the sources from where you read and rewrite the sentence in your own words. Citations thus can be sentences, quotes that you read from a source such as newspaper, magazine, pages, articles and books.
It role and importance is that without reading these articles you cannot write a good piece of writing. To write you have to read. Without reading you will not able to write for big essay, articles and columns.
We site a author by writing its last name then first name and then the year of publishing of books such as the name Arnold gestller, 2018 becomes Gestller, Arnold. (2002).