Modal verbs come before predicate verbs in sentences. If there is an auxiliary verb before the predicate verb, it is before the auxiliary verb. In interrogative sentences, modal verbs precede the subject.
I can see you. Come here.
I can see you. Come here.
He must have left.
He must have left.
what can I do for you?
Can I help you?
How dare you treat us like this!
How could you treat us like that!