macOS makes it easy to add "Input Sources" that you can toggle from your top menu bar. Write in another language on Mac - Apple Support
Update: Switching Keyboard Layout to French (AZERTY) change keyboard to french
To better support French-language typing, improve efficiency for bilingual tasks, and align with our standard operating environment, we will be switching the default keyboard layout from [e.g., QWERTY / English US] to French (AZERTY) effective [start date]. macOS makes it easy to add "Input Sources"