Simplifier belong to the 1st
group. Simplifier is a common french verb.
Simplifier is conjugated the same way that verbs that end in : -ier
Simplifier is conjugated with auxiliary avoir
Simplifier verb is
direct transitive, intransitive.
French verb simplifier can be conjugated in the reflexive form: Se simplifier
verb is a direct transitive verb, so passive voice can be used.