You can change WordPress url in phpmyadmin or Admin area of WordPress. If you can’t login, you can add following code to wp-config.php to force change WordPress URL.
define('WP_HOME','https://www.NEW-DOMAIN.EXTN');
define('WP_SITEURL','https://www.NEW-DOMAIN.EXTN');
Here are some WordPress plugins that help you move site from one domain to another.
Velvet Blues Update URLs
This plugin allow you to change WordPress URLS from old to new when moving WordPress.
https://wordpress.org/plugins/velvet-blues-update-urls/
WordPress Importer
Import WordPress post from one site to another.
