Je mange du pain.
English: I eat some bread.
Partitive articles in French are words used before uncountable or mass nouns to talk about 'some' or 'a part of' something, like food or drink.
Use partitive articles in French when you talk about an unspecified quantity of something you cannot count, such as food, liquids, or other materials. For example, when you want to say you eat or drink some of something.
Je mange du pain.
English: I eat some bread.
Elle boit de l'eau.
English: She drinks some water.
Nous achetons de la confiture.
English: We buy some jam.
Ils prennent des légumes.
English: They take some vegetables.