Drupal - How to change my base URL

go to yousite/sites/default and open the settings.php file and find $base_url and change it to the new value (somewhere around line 270).

NOTE : settings.php is a read-only file, you need to clear the read-only flag first to make the changes. You'll need to restart the server to update the changes.

There is a global variable called $base_url that you can set in sites/default/settings.php. Try changing its value.