WordPress Multisite is a powerful tool that allows you to administer several WordPress websites from a single panel, including installing a specific theme on all the websites in the network.

  1. Log Into the Multisite Dashboard (www.example.com/wp-admin/network).
  2. Go to Themes > Add New.Adding a theme to Multisite
  3. Click Install on the theme you want to install.Installing a theme to Multisite
  4. Click Network Enable.Enabling a theme to the Network with Multisite

Now the theme is installed on all the websites, but you still need to activate it to use it.

  1. Now go into your website Dashboard (www.example.com/wp-admin).
  2. Click Appearance > Themes.Activating a theme on a website
  3. Click Activate on the theme you’ve just installed.Activating a theme on a website