README updated

README.md

@@ -4,6 +4,23 @@ PapermergeJS is frontend part i.e. web-based user interface of Papermerge
 Document Management System. It is meant to be used in conjunction with
 [Papermerge REST API backend server](https://github.com/papermerge/papermerge-core).
 
+## What is Papermerge DMS?
+
+Papermerge is an open source document management system (DMS) designed
+for **digital archives**. Instead of having piles of paper documents all over
+your desk, office or drawers - you can quickly scan them and configure your
+scanner to directly upload to Papermerge DMS.
+
+## What is Digital Archives?
+
+Simply put a digital archive is a scanned document. In broader sense, digital
+archives are documents whose content does not change in time; a good example of
+such documents are PDF files. If you take a picture of a document, you'll end
+up with a "scanned document" in png, jpeg or whatever format that picture is
+stored. In context of papermerge a picture of a document made with you mobile
+phone is also a digital archive.
+
+
 ## Prerequisites
 
 In general, all you need to run this application is a modern web browser like