If you want to delete a document, right-click the document and select Delete from the context menu. The document is not lost permanently, but it becomes deleted and can still be found by performing a detailed search (see Deleted under Status).
Please note, however, that you can see deleted documents only if you have the appropriate permissions. If you have the system administrator permissions, full control of vault or the right to see and read all objects (including deleted ones), you can use a view that shows all the deleted documents. Refer to New View and Undelete.