Thank you for your question Cerrah. One of my team came up with the following thoughts.
Here are some quick thoughts on those questions. Firstly all materials are made of atoms and all atoms contain electrons. In some materials some of the electrons can be made to leave their atom and move to other atoms. This is what happens in metals. In metals an outermost electron can be persuaded to move from one metal atom to another. This can sometimes be by heating the atom, another way it attaching the metal to a battery. More later.
A little extra …….when an electron leaves an atom for the next atom this is followed by the atom that received the electron losing one of its own to the next atom ….eventually this line of moving elections meets a piece of wire which is different, it is usually thinner or made of a different metal which is more difficult for the electrons to move through …..the difficult movement causes a lot of heat…..the wire heats up and begins to glow ….. light is formed. Electrical energy is converted to light energy. Hope this helps.