Hot water is water that is very warm. You would likely wash your hands in hot water or clean your dishes using hot water. Boiling water is extremely warm or very hot water - it is when water reaches 100 degrees centigrade. You would typically use boiling water when cooking food.

"hot water" and "boiled water" > I like to have some hot/warm/lukewarm water pls = This just mean that you want some water of that degree of temperature. I like to have some boiled water pls = this just means that the water you want have to go through the process of boiling first, meaning the water has been heated up till it was bubbling. You never ask for boiled water in a restaurant, because hot water is definitely boiled in restaurant in order become hot . Unless, there is some water, say, left under the sun till it's hot (hot water), then you may want to say this : Could you boil the ( hot ) water for me so that I can drink it ? ( to kill the germs)

Just to extend on Gareth's answer - note that he wrote "boiling water", not "boiled water". Boiled water is sterile. You boiled it to kill any germs, then you let it cool down. This means that boiled water can be any temperature.

boiled water for cooking