There are two types of articles: definite and indefinite. The definite article is "the" and is used to refer to specific or particular nouns. The indefinite article "a" or "an" refers to nonspecific or general nouns and is not used with plural nouns, uncountable nouns, or material and abstract nouns. Examples are provided for the different uses of definite and indefinite articles.

3. Types of article
There are two type of articles.
definite article : the
Indefinite article : a , an

6. 7. Deserts ( the Sahara )
8. Directions ( the + east , west, north & south )
9. Historical buildings ( the tajmahal )
10. Heads of institutes ( the principal )
11. Plural name of countries:
USA ( United State Of America )
UK ( United Kingdom)
12. Heavy bodies related to human and earth.
And range of mountains
( the sun , the moon , the Himalayas )

7. 13. Superlative degree of adjective
( the most intelligent , the tallest )
14. Comparative degree followed by of :
He is taller of the two.
15. An adjective to represent the whole class of
it ( the poor )
16. A singular noun to represent the whole
class of it ( the lion )

10. 6. Language ( the Urdu)
English is a easy language.
The English language is easy to understand.
7. Man and woman ( the man )

11. Indefinite article (A/AN)
indefinite article are not refer to
a specific thing but to a general idea.
Example :
I have bought a book.
A book is to read.

13. Do not use a/an
1. With plural noun
2. with uncountable noun (an ink , an milk )
3. wit material and abstract noun