can we use word heat energy instead of thermal energy?What is difference between them?

Yes, we can use the term "heat energy" instead of "thermal energy", but they do not mean exactly the same thing.

Thermal energy refers to the energy contained within a system that is responsible for its temperature. It is the total of all the kinetic energy of all the particles that make up that system. It is dependent on the speed of the particles, the number of particles (the size or mass), and the type of particles in the system. Thermal energy can be transferred from one object or system to another in the form of heat.

Heat energy, on the other hand, is the energy that is transferred from one body to another as a result of a difference in temperature. In other words, heat is the movement of thermal energy from a warmer object to a cooler one.

So, while these terms are often used interchangeably in casual conversation, they actually refer to different, though related, concepts in physics.