Thermal energy is the heat that a body or system absorbs due to particle motion within the body or system. It basically refers to the capacity to do work.
Thermal energy is of three types or ways of transferring heat.
Conduction,
Convection and
Radiation
Conduction:
“When heat is transferred due to the vibration of the subatomic particles in their mean positions, the process is known as conduction.”
Convection:
“When heat is transferred due to the actual motion of the particles, the process is known as convection.”
Radiation:
“When heat is transferred from one place to another through infrared electromagnetic waves, the process is known as radiation.”