Select Sites Metabox

Select Sites is a metabox that is used in almost all MainWP Sections, and it's very important. Nearly every action performed in the MainWP Dashboard will require you to select Child Sites for it. For example:

Searching for Posts, Pages, Plugins, Themes, Users,...
Publishing new content on your Child Sites
Installing new Plugins and Themes on your Child Sites

It lists all websites that are connected to your MainWP Dashboard. To select a site, check the checkbox in front of the Child Site name. To un-select it, cancel the checkbox selection.

Sites that are disconnected will appear as disabled in the list, and the selection won't be allowed. The reason for this is very simple, MainWP Dashboard can't update a site that is not properly connected.

By understanding it better, you will be able to save some time in your daily routine in using your MainWP Dashboard.

Selection By Site and By Group

You can select sites By Site or By Group. In the By Site mode, you can select all, one or multiple individual sites, and in the By Group, you can select all, one, or multiple individual groups. Selecting a Site Group means that all sites that have been added to the group will be included in the selection.

Quick Selection

In the top-left corner of the Select Sites metabox, you can find the select All / None quick selection buttons.

Sites Filter

In the top-right corner of the metabox, type in the name of a Child Site that you want to find and select, and sites will get filtered so you can easily find the wanted website. This feature comes in handy when managing a large number of Child Sites.

Source Article: https://kb.mainwp.com/docs/select-sites-metabox/