The Sun has 6 different region which constitutes it completely which are namely from the outermost part to innermost part as follows,
Corona, Chromosphere, Photosphere, Convection Zone, Radiation Zone, Core.
Explanation:
The innermost part is the core of the Sun which has its 25 percent of presence in respect to the radius of the Sun. Next is the Radiation zone comprising the 45 percent of the radius with another 30 percent covered with the convection zone of the Sun.
The atmosphere of the sun contains the outer three parts as Photosphere, Chromosphere and the Corona. The level of heat increases on the way up in atmosphere.