Articles are funny things. They're hugely important in languages where they are used, yet other languages get by quite happily without them. Unfortunately, anyone writing for an international audience will usually have to learn English, and that means using articles. For Indians, Japanese and many others, it's a hard skill to master.
Articles determine the role of a noun in a sentence, giving it history and context. There are two kinds: the definite ("the") and the indefinite ("a" – or "an" if the noun starts with a vowel sound*).