Determiners are used with nouns to clarify the noun.
The type of determiner used depends on the type of noun.
Singular Nouns - always needs a determiner
Plural Nouns - the determiner is optional
Uncountable Nouns - the determiner is also optional
There are about 50 different determiners in the English language they include:
Articles - a, an, the
Demonstratives - this, that, these, those, which etc.
Possessive Determiners - my, your, our, their, his, hers, whose, my friend's, our friends', etc.
Quantifiers - few, a few, many, much, each, every, some, any etc.
Numbers - one, two, three, twenty, forty
Ordinals - first, second, 1st 2nd, 3rd, last, next, etc.
Following are the four types of determiners:-