At pointAB the Solid ice is gaining heat.
At point BC the ice is melting. The heat energy supplied changes the solid ice into a liquid.
At the point CD the water formed absorbs heat and the temperature increases.
At point DE the water changes into a vapour. The heat energy supplied is used to overcome the force of attraction between the water particles.During change of state the temperature of a substance remains constant but the substance continues to absorb heat energy.The temperature remains constant because the heat energy is used to overcome the force of attraction between the particles in a substance.