How to benefit neural network ? • /r/MachineLearning

How to benefit neural network? As long as I know, Deep Learning uses an abstract neural network, but how to benefit this neural network? Is it directly interogated by a software to help it to answer the user's question, or is it used to only generate a model that can be used by the software? In other words, does the neural network still works during software processing after the model is generated (regardless model evolution)?