On inception of a new work item, the Document Repository Quick Folders function can create a new set of folders within the left-hand Quick Links section of the documents view (the left-hand list of folders), as seen in the image below:

When a file is added to a quick link folder, a corresponding folder is created in the main body of the documents view (the right-hand list of folders), and the two are linked together.
Clicking on the left-hand folder (e.g. Evidence in the example above) will automatically open the contents of the right-hand folder of the same name.
To maintain the Quick Link folder list
An option set controls the Quick Link folder list. The core out-of-the-box option set is Matter Document Repository Quick Links.

This behaves like any other option set. A hierarchical structure can be created (toggle Allow Hierarchy on), allowing multiple levels of sub-folders:

This option set can be accessed via the Document Repositories widget in the general settings screen for a work type. Click Edit to view the option set.

Work types whose document repositories are not inherited can be edited. You can also add multiple repositories with other quick links, for example, a dedicated Attachment folder.
Note that each derived work type will inherit the option set from its parent. This cannot be changed via the UI—it can only be undertaken via a script, and you need to contact support for help with it.

However, the parent option set can be changed. Click on the inherited link to navigate to the parent work item.
On the parent work item, click on the edit icon and select a different option set from the list available:

This will affect all child work types that inherited the option set.
Portal Designer
The quick links feature can be disabled for a specific work type.
Note that the Repository Explorer widget contains a toggle Show Folder Structure:

Toggle this to Off to hide the quick links for this work type.
Default document folders for a repository
The default document folders for a repository are maintained in the Document folders option set (this option set's system name is document-classes by default).
