To create multilingual websites in Craft CMS, you must first establish multiple sites through the Control Panel Settings
The first step for a multilingual website with Craft CMS is to create at least two sites. You can do this in the backend in the Control Panel Settings, in the Sites configuration.
One thing to note right away is that Sites are part of the project config, so they’re tracked in the config folder. That means you can only create and configure sites in a development environment. You can’t change or add sites in the production environment, where config changes are disabled.
The concept of Sites in Craft CMS is used for both multi-language and multi-site setups, so you can create both multilingual sites, and even create multiple websites that each come in multiple different languages.