When to use une or la in french?

Answer 1

une and la are feminine articles in French. 'une' is translated by 'a': une voiture = a car (that could be any car); 'la' is a definite article, translated by 'the'. La voiture = the car (you know what exact car we are speaking of)

Answer 2

"Une" is used to refer to a singular feminine noun, while "la" is a definite article used before a singular feminine noun. "Une" is used for indefinite articles, while "la" is used for definite articles.