In order to keep SharePoint lists indexed, organized, and
readily searchable, many people rely on folders.  In SharePoint 2013, default, only Document
lists display the New Folder icon on
the Ribbon.  This can be easily remedied
adjusting your settings to make the New
Folder command available. In this article, we’ll show you how to display
the New Folder icon on the Ribbon
for all of the different types of SharePoint lists.

To begin, go to any list on your site and select List Settings from the Ribbon.  In this example, I will be configuring the
list using the Custom List settings
option.

From the Custom
List settings, select Advanced Settings:

In the Folders section,
under Make New Folder command available,
select the Yes radio button and
click OK:

Return to your list.
Under the Items tab, you will
now see the New Folder icon displayed
on the Ribbon: