Classical conditioning applies mostly to operant conditioning applies mainly to

Classical conditioning applies mostly to "biological response". Operant conditioning applies mainly to "voluntary behavior".

Classical conditioning alludes to a learning system in which a biologically potent stimulus(e.g. sustenance) is combined with a formerly unbiased boost (we can take food as an example). It additionally alludes to the taking in process that outcomes from this matching, through which the neutral stimulus comes to evoke a reaction that is normally like the one inspired by the strong stimulus.

Operant conditioning refers to a sort of learning in which the results of conduct are controlled so as to increment or decline that conduct later on.

Classical conditioning is a type of learning in which a neutral stimulus comes to elicit a response after being paired with a stimulus that 
would elicit the same response naturally.
Classical conditioning applies mostly to involuntary behavior; operant conditioning applies mainly to voluntary behavior, where voluntary behavior includes actions that are taken by choice, rather than by reflex.