Infinitive mode
The infinitive mode is impersonal, that is to say that it is not preceded by the pronouns "je", "tu", "il", "nous","vous" and "ils". The most common use of the infinitive is to be able to designate a verb outside of its conjugation.
Verb "avoir"
But the infinitive especially allows the verb to be able to function as a noun without losing its verbal properties.
Je fais travailler mon dos.
It is clear here that "mon dos" is the subject of the verb to work while "travailler mon dos" takes the sense of a complement. The infinitive thus allowed us to use both the verb in its nominative form while keeping its meaning of verb.
Infinitive tenses
There are two tenses in this mode: present and past.