A modal is a type of auxiliary (helping) verb that is used to express:
are used to express the same things as modals, but are a combination of auxiliary verbs and the preposition to.
Modal phrases (or semi-modals)
ask questions even more politely than you would with “can”
Could
state a logical deduction
Ought to
The most polite out of all the modal verbs to ask permission
May
use it to express decisions about the future
Will - Shall