With the proper permissions – Full Control, Design, or Edit – you can activate or deactivate specific SharePoint features for your site. As an example, working with a Team site you can choose to activate a feature that creates a Microsoft OneNote notebook in the Shared Documents library of the site. Or perhaps you want to add community functionality such as discussion categories, content and people reputation and a members list.
To activate or deactivate features for a site
Navigate to the site you want to configure.
Click Settings and then click Site settings. In SharePoint Online, click Settings, click Site contents, and then click Site settings.
On the Site Settings page, under Site Actions, click Manage site features.
Click Activate next to the feature you want to activate on the site, or click Deactivate if you want to turn off the feature on the site.