Genderfluid is a gender identity that changes. This is both a label that people use for a specific identity and an umbrella term for any gender that changes in any way, such as genderfae or genderflux.
Genderfluid people will sometimes change pronouns depending on which gender they identify as at the moment, but many will go by one set of pronouns, commonly they/them/their/themself. Genderfluid individuals will often choose a gender-neutral name as well.
Genderfluid is a umbrella term for any gender what changes. This includes genderflux and many other.