Plugins can be ‘Network Activated’ or ‘Network Deactivated’ via the Plugins page on the Network Admin dashboard on a WordPress multisite install.

When a plugin is network activated that plugin is automatically activated network wide and is available for use on all sites across the network.

If a plugin is ‘network activated’ it no longer appears in the Site Admin dashboard at all.  Only a Super Admin user is able to deactivate a “network activated’ plugin via the Plugins page in the Network admin dashboard.

Plugins are network enabled as follows:

1. Click on Plugins > Installed Plugins in the Network Admin dashboard.

2.  Select the plugins you want to make available to all sites by either:

• Clicking on Network Activate below the plugin name.
• Selecting all the plugins you want to enable, then select Network Activate from the Bulk Actions drop down menu and click Apply.