Deleting documents and properties in SimplerQMS is not possible. 

When a document was created by mistake or is no longer needed, it can be placed into Not Current - Archive. This option is available of the state of the document is in New Draft. The Author, Responsible Person, and Process Manager can make this state transition. 

For an Effective document, you can Route for Retirement in case you no longer want to use the document.  You can refer to this workflow: 

In a property, option "Not Current or On Hold" is available at any stage.