1. Add your abbreviations, code words, isms, and proper names to your personal dictionary. In some cases, such as Gmail, you can add new words directly to the app. The process depends on your device and its operating system. For example you type a word that’s not in the dictionary, and it’s overwritten with a slightly different word (such as this being replaced by that); hitting the delete button may revert it to the original word you typed. Or you may have to re-type the original word all over again. In any case, the word in question will then have a red underline. Tap or double tap on that word and you can choose “add to dictionary” or “replace” to save the entry.
2. Personalizing third-party keyboards. When using a third-party keyboard, adding new words will involve a different process.
If you use Swiftkey, most of the time the app will learn from your behavior and stop correcting words you use frequently. If that doesn’t happen, though, you can use the prediction box, which appears above the keyboard to add it to the dictionary. In Swype, you can add new words by tapping on them in the word choice list (WCL); long press on a word to remove it from the dictionary.
3. How to enable and disable autocorrect. Of course, you don’t have to use autocorrect at all if you don’t want to. Most third-party apps offer the option to disable it, as does the stock Android keyboard. Go into settings, Language & input, Google Keyboard, and tap on Text correction. Here you can turn auto-correction on or off, and adjust other settings such as blocking offensive words, showing suggestions, suggesting contact names, and showing next-word suggestions.