When you boil water, it reaches a temperature of 212 degrees Fahrenheit, which causes continuous and vigorous bubbles that release starch and make the rice sticky.
Boiling water also has a higher rate of evaporation, which can result in undercooked rice or an unpleasant combination of sticky, scorched, and crunchy rice.
Simmering rice has a lower temperature between 185 and 205 degrees Fahrenheit and generates smaller bubbles for a slower, steadier cooking process that allows even cooking.
Once the water is boiling, add salt and reduce the heat until the water is simmering. Cover your pot and simmer the rice for the recommended time without lifting the lid.