Usually, the object comes from verbs and particles.
Example:
I looked up the word in my dictionary.
I looked it up in my dictionary.
However, with several verbs that can be separated, the object can come before or after the particle.
with multiple verbs that can be separated, the object can come before or after the particle.
Example:
Switch the light off.
Switch off the light.
Switch it off.
Usually there is no standard way to classify whether
phrasal verb can be separated (separable), (inseparable), transitive or intransitive.