Some organizations want their documents’ file names to automatically be set, depending on how they are tagged, e.g. that the first HR-related policy’s file name would be “policy-hr-001”, the second “policy-hr-002”, etc.
We do not recommend our clients to set up rules that automatically set the documents’ file names, based on business rules, as this would radically change the standard SharePoint behavior, having to maintain a custom solution that eventually might brake when new SharePoint updates are released by Microsoft. If documents have meaningful file name e.g. “Contoso’s Document Management Policy”, you can directly understand the document’s content by reading its name, also making it easier to share documents, without needing to describe the documents’ content.
If you however would like to be able to reference to a document’s ID, rather than it’s file name, there are several ways to do this. See this page for further information: Do documents in SharePoint have a unique ID?.