iOS’ autocorrect can become a bit annoying when a correctly typed word is replaced with something else. It is because the word isn’t in the iOS dictionary. If you are using some words frequently, it is always better to add them to your iOS dictionary. Here is the quickest way to add new words in iOS. To do so, open Safari and type the word in the search field. Once you press the GO button, iOS will stop correcting that word for you. You can also add the words to the shortcuts list (which syncs across all your devices). For that go to Settings then General then Keyboards and then Shortcuts.