Heat is one type of energy. It will make a body warmer and its absence make a body cooler.
It will be produced due to the friction and collision molecules.
Heat energy will transfer from one object to another depending on the temperature difference of the objects.
Sunlight, magma emitted, and from volcanoes, burning fuels are the natural source of heat energy.
If a system of particles becomes excited by taking energy, then the particle oscillates or vibrates rapidly, it is sure that heat energy produces in the system.
Thermo is a Greek word, which means heat. So, thermal energy is the other name for heat energy.
Thus, heat energy is also called as thermal energy.