BAD IDEA
Can I boil water and freeze it to use boiled water later and save time?
Sure, you can freeze boiled water, but thawing it later will take more time than just boiling fresh water.
Boiling water and freezing it sounds smart until you realize thawing frozen water is slower and more hassle than a quick reboil. Besides, freezing can change taste and texture if you store it too long. It's simpler and faster to just boil fresh water when needed. So, save your freezer space and your patience.