Qué, cuál, and cuánto are Spanish interrogative adjectives. An adjective is a word that modifies a noun, and interrogative means questioning, so interrogative adjectives are adjectives used to ask the questions "what," "which," and how "much/many."
Who, what, which one? Use interrogative pronouns to ask these questions, which are a little more complicated in Spanish than in English.
Asking questions in Spanish is pretty straightforward. There are two main kinds of questions: closed questions and open questions.