What kind of verb is do?

Answer 1

"Do" is most often a main verb that can be either transitive or intransitive. "Do" is also used as an auxiliary verb to form what is sometimes called an "emphatic" tense, as in, "How Fidel Castro does go on in his speeches!" but is also used as a compound form for asking questions, such as "Do you plan to go to the fair?"

Answer 2

"Do" can function as an auxiliary verb (helping verb) or a main verb in a sentence, depending on its usage. It is often used to form questions, negatives, and emphasis in English sentences.