To delete a document first go to main Document Tab and select the document you want to delete. In this case we will use a PDF document called test.
Once you click the test document you will be redirected to main documents page. By default you will be redirected to Overview Tab. Once there click on Settings Tab.
At the bottom of the page on Settings Tab there is a button for deleting the document:
Upon clicking on the button a confirm modal with be shown where you can delete the document or stop the operation:
After document is deleted you will be redirected to main documents page.