Polylang (multilingual plugin) allows you to have a different domain name by language.
If you use this option, you might also like to have an XML sitemap by language / domain.
To do this, you must have version 3.7.3 of SEOPress at least.
Copy and paste the code below into your functions.php file of your theme (child theme preferred) or into a must-use plugin.
Required version: 3.7.3