An Article is a word that is used before a noun to show whether the noun refers to something specific or not. These are a, an and the…
Examples:
Indefinite Article
I need a house 
In the above sentence we find the article ‘a’. It shows that I do not need a specific house. I can have any house.
I would like an apple.
Once again, above we find the article ‘an’. It shows that the speaker does not need a specific apple. He can have any apple. The difference here is ‘an’ is used when the word begins with a vowel, ie
umbrella
elephant
iceberg
however
If the first letter of the word is a vowel, but sounds like a consonant, then we use ‘a’
A used car, a useful gadget
If the first letter of the word is a consonant, but sounds like a vowel, then we use ‘an’
an hour, an honest woman, an eye
Definite Article
I want the puppy 
Here we see that I want a specific puppy, not just any puppy.
‘The’ can be used before both singular and plural nouns.
Examples:
“The flower he gave her was very beautiful.”
“The flowers on the table are nice.
