Only Content Managers and Workspace Managers have the ability to delete a collection.
Unlike deleting a workspace, deleting a collection does not require the Content or Workspace Manager to move lists and content items out of that collection before it is deleted. The process of deleting a collection will not delete any existing lists or content items within the collection. When a collection is deleted, any lists or content items simply get moved and organized back into the workspace.
In summary: Deleting a collection will only delete the collection itself. The collection deletion process does not delete any lists within that collection. Lists are returned to the workspace after the collection is removed. Only the collection gets deleted.
Select the collection in the left menu tree and click on the 3-dot menu.
Choose Delete
A dialog will appear prompting you to confirm the deletion
To proceed with permanently deleting the collection, click the Confirm button, otherwise click cancel.
The collection is deleted and removed from the left menu tree. Any lists are now accessible under the workspace.