There are multiple options when you choose to make your website multilingual. Choosing one is dependent on your project's needs. Please watch a great explanatory video on the subject at WordPress.tv.
I personally use Polylang plugin (or you may need to use paid counterpart, the WPML). However, the clearest and safest solution is using WordPress multisite setup, which I've successfully used in the past (watch the video above for more tips on this setup).
- In-Depth WordPress Multilingual Setup Guide, https://kinsta.com/blog/wordpress-multilingual/