Question

How can energy be converted from one form to another form in simple words?

Answer 1

It is a well known fact that energy can neither be created and nor be destroyed but can be transformed from one form to another. Now talking about your example in a typical light bulb electrical  energy is converted into light energy and heat energy.
Hope this may help....

Answer 2

We know that energy can be transformed from one form to another by many ways
1. Transformation of thermal energy into electrical energy in thermal power plant
2. Transformation from machanical energy to electrical energy through generator
3. transformation of electrical energy into machanical energy in motor
4. transformation of potential energy of water in dams to kinetic energy of water in rivers
and many more .