An infinitive is a verb form that consists of the word to followed by a verb, i.e., to jump, to listen; however, an infinitive is NOT used as a verb! It can function as a noun, adjective, or adverb....
you are derives from the infinitive of to be. The infinitive that belongs to 'you are' is 'to be'.
To have
when a verb has "to" in front of it, it is known as the infinitive e.g. To play To run To jump