The article deals with the questions related to typology of text. It clarifies the concept of "text type" as related to the concept of "speech genre". It analyses three types of text - explanation, argumentation, and instruction. All of them refer to the mental sphere of human activity, which, on the one hand, unites them within one group of cognitive-voluntive texts, and on the other, juxtaposes them with description and narration. We consider the substantial and intentional bases of these texts, the method of presentation, and specific language tools as stable characteristics peculiar to each type. The problems discussed in the article correspond to the linguo-didactic task of developing text types for understanding and speech production.