I received the item is used when emphasizing the time you received it, it is past simple (not past perfect).
e.g. I received the item an hour ago.
I have received the item emphasizes that you have something new, it has arrived and you share it with whoever you want, it is present perfect.
e.g. I have just received the item. OR I have received the item I've been waiting for. OR Look! I have finally received the item.
However, AmE (in my opinion) prefers past simple in many occasions over present perfect. So, unless this is a school leaving exam question, I would not bother with it so much in daily conversations or correspondence.
Hope I helped at leas a little bit. :-)
«I received the item » uses the Simple Past tense and should include a past time indicator such as yesterday, last week, two days ago....
«I have received the item» uses the Present Perfect tense even if it is a past moment, but we do not know exactly when it happened in the past.
Here I would choose, « I have received the item», but using the other form in the Past you would also be very well understood.