Storing entites? [kryonet]

Well i am working on a multiplayer game, and i have like enemies that spawn randomly so i was wondering should the server spawn the entities like send the x,y of that entity and the client would render it? And the same question for the particles should i store the in server or every client would generate(server is telling the client where to generate them) them for like example fire particles, but it wouldn’t be the same for anyone? I done this with some cubes moving around, this seams more complex!