Apple Keyboard in Dutch

You can add, adjust, or remove new language keyboards at any time in iOS by doing the following:

1. Open the Settings app then go to “General” and “Keyboard”
2. Choose “Keyboards” and select “Add New Keyboard” – tap on any alternate language keyboard to add that to the list of available keyboards in iOS which you’ll then be able to gain quick access to

Changes the settings:

Mac -> System Preferences -> Language & Region.

iPhone -> Settings -> General -> Language & Region.

For Mac keyboard:

Write in another language on your Mac - Apple Support

Hi

Go to Settings — General—- Keyboard— Tap Keyboards—Add new keyboard as per your choice.