It is a verb that is conjugated like "aimer" (to love) in the present tense:
* Je préfère (I prefer)
* Tu préfères (You prefer)
* Il/Elle/On préfère (He/She/One prefers)
* Nous préférons (We prefer)
* Vous préférez (You prefer)
* Ils/Elles préfèrent (They prefer)
You can also use the past tense, future tense, conditional, and other conjugations, just like any other French verb.