How are electromagnetic waves formed?

Answer 1

they are formed when a electric field and a magnetic field couple.

When ever a charged particle undergoes an acceleration it emits electromagnetic radiation. Therefore when an electron 'jumps' from a high energy quantum state to a lower energy quantum state it produces em radiation of a particular frequency.

And, more precisely, EM waves are created by accelerating a charge. An electron at rest (or cruising at constant speed) has a stable electric field radiating outwards (really inwards for negative charge). If the electron is accelerated, a ripple in the field radiates outward with the speed of light, with the strongest effect perpendicular to the electron's vector of acceleration and weakest part (zero) along the vector. The electric field fluctuation is in any plane along the vector, and the magnetic part is in the plane perpendicular to that and the vector.