Previously, we have used another DMS as our content manager and in this DMS, documents was capable to consist one or more than one file as attachment. and metadata was the key point of document. this definition made us able to upload more than one scan photo's for a single physical receipt document.
so, In Alfresco, can we have a document that could have bunch of files (probably with various content type) in a single document ?
Yes, you can do it, but it requires some configuration. You can use Alfresco Data Lists component to store metadata-only objects. Then you can attach as many files as needed to the object:
Also there is open-source extension for Alfresco that extends this page with document id, attaching master data etc and it contains a number of default document types out-of-the-box (like incoming documents, contracts etc), but it works only on Alfresco 4.2 (not new Alfresco 5.2) as for now http://old.alvexcore.com/en/product/features/documents/