Here is the most simplistic picture that I could think of to answer your question.



I hope it would help!

In a nutshell, all those neurons which reside in the central nervous system are called "inter-neurons"; whereas, all those neurons which combine together to form the peripheral nervous system are "motor neurons" and "sensory neurons".

I do not want to go into much more detail, but let me tell you that motor neurons are also referred as "efferent neurons", and sensory neurons as "afferent neurons".



NOTE: I did not include spinal cord in this elaboration, but let me tell you that spinal cord and brain both constitute to form the CNS(central nervous system).

P.S: If you want more details, do let me know!

-israr