Learning is a fascinating process that varies from the rather simplistic classical conditioning seen in many organisms to more complex forms of learning, such as observational or insight learning, which require a degree of thinking on behalf of the learner. Classical conditioning is fairly simple and straightforward: if you ring a dinner bell every time you serve dinner, people (an animals) will learn to associate that bell with dinner, and that may very well get their digestive juices flowing.
Operant conditioning builds upon classical conditioning in the sense that animals now react consciously to the stimulus and make decisions based on what they know will happen next. A parent may learn that ringing the bell gets their kids to come in for dinner faster, so then becomes conditioned to ring the bell every time.
Still higher levels of learning, such as latent learning, might arise when a child learns to tell time and start heading in for dinner on their own.
My favorite form of learning is insight learning, the "ah-ha!" moment when someone suddenly figures out something that was previously difficult for them. It seems to me this is the most useful form in our current world.