It has always been said that energy cannot be created or destroyed. Energy is something that exists in this world, and there is an option for energy to be changed. It can transform from one type of energy to another, but it does not mean that it will go away. There are different things that energy will go through, but it will always be there.
An item that is just placed in a room may not be moving, but it has energy. The moment that it is pushed or pulled, this means that the energy has already transformed. It has transformed from potential to kinetic energy. All types of matter will have a positive energy that can change depending on the processes that you will do.
Yes, you can. If you are swinging a punch you have created kinetic energy and if you decide to stop that punch in mid-air then you have "destroyed" the kinetic energy that was in the punch.