Of course, not every vendor is skilled at document control. Whether they provide you a list of documents (fabrication vendors), or you help them by auto-generating the full list of required docs (instrument & valves vendors) DocBoss helps you track missing documents.
Query by vendor, project, tag, due date etc. Create expedite requests, and fire them out to your vendor. Again if using auto-generated registers, you could easily issue the complete document list (not just VDR codes) when you issue the PO.