How to permanently turn off check spelling while typing in macOS!

How to permanently turn off check spelling while typing in macOS - for each and every app. Whenever I turn off this option in anyone of my default or third party mac apps within a few seconds these option turns itself on automatically, so is there any option to turn this off permanently across each and every app? I have already tried each and every solutions mentioned in this question https://apple.stackexchange.com/questions/257528/cant-disable-check-spelling-while-typing-in-notes-in-osx-el-capitan-10-11-6 But still it automatically gets turned on!