A. You can adjust the auto-correct settings by going to Settings > General > Keyboard and toggling off 'Auto-Correction'. This will prevent the app from making automatic corrections, allowing you to type freely without interference.
B. If you prefer to keep auto-correct on, you can add frequently used words or phrases to your keyboard dictionary. Go to Settings > General > Keyboard > Text Replacement and add new entries for words that are often corrected incorrectly.