What is the difference between definite articles, indefinite articles and articles in Spanish? What are their functions? Isn't indefinite article plural?

Articles are divided into definite articles and indefinite articles. Both of them are charged with singular and plural crimes.

The definite article modifies a specific, well-known or unique thing.

Definite article: singular: EL, la, plural: LOS, LAS

The indefinite article modifies something that is not specific and arbitrary.

Indefinite article: singular: UN(O), UNA, plural: UNOS, UNAS.

Examples of definite articles:

Is that Juan? Hello, QUE, how are you? .

Which one is Juan? The boy who greets you (the boy everyone knows)

QUE time to sell Ersol?

When does the sun come out? (The only thing that exists: the sun)

Ivana is a student of QUE· Konosko.

Ivanna is the most beautiful girl I know.

This is PLATICANDO's youth team.

The athletes are talking (everyone knows who they are. )

Our friendship did not last.

Friends (of women) are not coming. The speaker knows which friends he is referring to. )

Examples of indefinite articles:

QUE· Matens? United Nations Library.

What did you give me? A book (generally refers to a book, not to mention the name characteristics, etc.). )

A piece of good news. I don't like QUE news.

I have good news (referring to a piece of news, but not revealing what it is). I am not interested in your news.

Is QUE a star? VOY· Antegar ·UNOS file.

What do you want to submit? I want to submit some documents (I didn't say what the specific documents are, and the questioner doesn't know).

Juan Tom? UNAS· Pastia.

Juan took some medicine.