Step 1: Login to your cPanel account.
Step 2: Select the File Manager option under Files.
Step 3: Navigate to your website folder (public_html) and search using wp-config.php file.
Step 4: Insert the following 2 lines and define your WP_HOME and WP_SITEURL in wp_config.php file.
+++
define('WP_HOME','http://mydomain.com');
define('WP_SITEURL','http://mydomain.com');
+++
Step 5: Finally click Save changes option.