Alright I've basically finished the existing manga and anime and I'm still confused. What's the difference between an emitter and a conjurer? What can each do that the other can't?
Emmiters are Nen users who are adept at separating their Auras from their bodies and using it for a variety of functions. Some examples being Leorio (who could emit his aura into creating a warmhole for carrying attacks). Emitters are also capable of transforming the separated Aura to look like certain shapes and objects. Pokkle for example, (renowned for using his Nen to take the shape of bow and arrow which he could use for offense).
While Conjurers on the other hand, have the ability to create physical objects using Aura. More adept Conjurers can even create laws and principles which are affixed to the object manifested from their Aura. An example being Kurapika's conjured "Dowsing chains" which were created with a principle of detecting lies and Aura.