Energy is the capacity to do work. Energy exists in various forms in the entire universe.
It may be light,sound,electric,magnetic,kinetic,potential,thermal energy etc.
As per the law of conservation of energy, it is neither created not destroyed. It can change from one form to another form.The total energy of the universe is always constant.
The process in which energy will change from one form to another form is called energy conversion.
There is also another terminology for energy conversion called energy transformation.
Energy transference is the process in which energy will be transferred from one body to another body.
Hence the correct answer to this question will be conversion and transformation