Partitive articles are used both in English and in French to express quantities that cannot be counted. While the indefinite article un, une, des is used with countable quantities un oeuf, des oeufs, etc., the partitive article is used before nouns that are indivisible or uncountable. In English, we use the article “some” to that end, but it is often omitted.
☞ Elle boit du café. She’s drinking (some) coffee.
☞ Elle mange des pommes.She’s eating (some) apples.