In english there are two types of articles, definite articles and indefinite articles:
Indefinite articles are A and AN, we use them when the noun is unknown, when it’s not a specific object.
when the noun begins with a consonant we use a, and an when the noun begins with a vowel (a,e,i,o,u).
|I saw a movie last night.
|The goal is scored by a player from that team.
|You eat an apple.
|I am an English teacher.
Definite articles: The is the definite article, we use it when we talk about an object that both the speaker and the listener know. it’s common for all the nouns.
|You see the picture on the wall, I bought it yesterday.
|The goal is scored by Ronaldo.
|The apple is delicious.
In some cases we don’t use any article, we talk about The article zero. for more details see this lesson:Article zero!