How to change the site name in WordPress
The default themes come prepackaged with WordPress such as the Site Title. During the set, the site title installation process, be sure to set up the site title.
Once the installation has been completed, you can change the site title at any time. Keep in mind that the site title is just a name displayed on the frontend of your site;
it can be any named anything.
To change the site title go to Appearance menu > Themes submenu > Customize button for the theme >
Site Title & Tagline or from general settings go to Settings menu > General submenu,
type in the name and click on the Save Changes button.