1. Go to System Preferences or Settings on your device.
2. Under Languages, add Chinese (simplified, mainland), and under Keyboard Preferences add Pinyin input.
3. You should now be able to toggle between English and Chinese keyboards.
4. If you want to input 中
, type its pinyin “zhong” and characters with this pronunciation should appear. Choose the one you want.
5. For more detailed instructions and screenshots, check out this website
or this one