A phrasal verb is a group of words that functions as a verb and is made up of a verb plus a preposition or an adverb (or both). It creates a meaning different from the original verb. There are a lot of phrasal verbs in English!
All modal verbs are auxiliary verbs, which means they can only be used with a main verb. Modal verbs cannot be a main verb. They are used to express ideas such as possibility, prediction, speculation, deduction and necessity.