Encapsulation is a technique in programming where the programmer hides the internal behavior of the object from the user. Encapsulation hide the inside view of the object from the user such that it only implements the behavior of the object. Usually the client does not need to know the detail of the program and that is exactly what encapsulation does.
Encapsulation hide the data for object and makes the variables as private, and expose only the property to access the private data which would be public. So, when you access the property you can validate the data and set it.
For example, let take a Mobile Phone and Mobile Phone company. Suppose you are a Mobile Phone company and you designed and developed a Mobile Phone design(class), now by using machinery you are making a Mobile Phone(object) for selling, when you sell your Mobile Phone the user only learn how to use the Mobile Phone and not how the Mobile Phone works.
Again, let consider a TV operation for example, the manufacturers encapsulate it with cover and we can only operate it with the remote and have no need to open the TV and change the channel.
In this regard, everything is in private except remote; so anyone can access to operate and change channel and not the things in TV.