The primary site name in WordPress is the name that is displayed in the header of your site. To change this, you will need to go to the WordPress Dashboard and navigate to the Appearance > Customize > Site Identity section.
From here, you can change the Site Title and Tagline, which will change the primary site name that is displayed on your site.
To change your primary site name in WordPress Multisite, follow these steps:
1. Log in to your WordPress account and go to the Dashboard.
2. In the left-hand sidebar, hover over Sites and click on All Sites.
3. Find the site you want to change the name of and click on Edit.
4. In the General Settings section, change the Site Title field to the new name you want.
5. Scroll down and click Save Changes.