Question

use of have to,has to,had to​

Answer 1

These modals are used to express certainty, compulsion, necessity, and obligation. In this video, Awal has also described the sentence structure and the correct form of verb to be used in such sentences. If you are looking for low level details on how to use Have to, Has to, Had to, this video is for you as a beginner.

Answer 2

Has to is used for explaining necessity

Had to is used for past tense of forcing

Have to is used for 2 or more people having necessity

Hope it helps