Question

Why do you think elements must be heated before they emit colored light?

Answer 1

I assume you must mean heated, and not hated. That sounds like a bad chemistry joke.

Elements need to be heated usually before they emit color because you need to add energy to excite the electrons in the atoms. When they go into an excited state, they eventually go back to the ground state. During that transition, the electron dissipates that energy in the form of heat, or they can emit a photon aka light.