With phrasal verbs, you can usually have a noun before or after the preposition.
Turn off the light. Turn the light off.
Look up the word. Look the word up.
Show off my new ring. Show my new ring off. (This one sounds a bit odd.)
However, when you use a pronoun, it goes between the verb and the preposition.
Turn it off. Look it up. Show it off.
(Some phrasal verbs don't allow words to come between the verb and the preposition, but I'm having trouble thinking of any right now.)