Background:

It might be needed to change WordPress site URL  for example from http://domain.com to http://www.domain.com and vice versa.

Workaround:

My test blog’s original site URL was http://tutorial.kaysariqbal.com; intend to prefix the site with www so the site will look like http://www.tutorial.kaysariqbal.com. To make Change WordPress Site URL i had to work on cPanel of the site. There are many ways to change WordPress site URL (read more); i will implement the method of editing the “wp-config.php” file. Steps are below:

1. From the cPanel open the “File Manager”
2. Locate and open the directory “public_html“
3. Backup your current “wp-config.php“ file before making any changes
4. Open the “wp-config.php“  file to edit by clicking the “Edit” button from the “File Manager” menu
5. Appending the below two lines in the “wp-config.php” file

   • define('WP_HOME','http://www.tutorial.kaysariqbal.com');
     
     define('WP_SITEURL','http://www.tutorial.kaysariqbal.com');

6. Save the changes to “wp-config.php” file
7. From the cPanel Go to the “Redirects” under the “DOMAINS” 
8. Add a permanent redirect from “http://tutorial.kaysariqbal.com” to the “http://www.tutorial.kaysariqbal.com” with the option “Do Not Redirect www.”
9. From cPanel go to the WordPress
10. Select the “Edit” under “Options”  to the desired site link
11. Change the URL to “http://www.tutorial.kaysariqbal.com“
12. Done all things required; time to surf the site with new URL. 🙂