I have created a custom list named “K2 Workflow Tutorials” in which K2 workflow will be created to delete folder in document library. Please refer to my previous article to create a K2 workflow in SharePoint 2013 Online.
Go to K2 designer, drag and drop Delete Folder step from the Documents workflow steps in the ribbon interface.
Select a site collection, enter the folder name and then click on Next button.
Specify the document library in which you want to delete the folder and then click on Next button.
Specify whether to use recycle bin and then click on Finish button.
Deploy the workflow. Create a new list item in “K2 Workflow Tutorials” list with title field value as “TEST”. After few minutes the workflow will be completed and the folder named “TEST” will be deleted from the document library “K2 Workflow Documents”.