Heat is transferred in a number of ways. The most prevalent are conduction, convection, and thermal radiation. A good example of conduction is a pot cooking on a stove's burner. The metal on the pot's bottom 'conducts' or carries the heat energy to the pan (and the contents of the pan). Convection heating involves the flow of a liquid or solid moving from hot to cold due to expansion. Think circulation, like a warm air vent warming up a room. Lastly, radiation transfers heat radiantly...like sunlight on the sand at the beach.
heat is energy as it spontaneously passes between a system and its surroundings, other than as work or with the transfer of matter.