Classification of PDF files Go to the "Documents" menu item and click "List of unclassified". Go to the viewing mode by clicking the "Classify" button. You can use the Next and Previous buttons to move from file to file. In order to classify a document, select the counterparty and the type of document.Then click the "Save" button. Document types There are currently 3 types of documents: invoice agreement annex (used to correct / overwrite contract parameters)