A document can consist of one or more versions, and all versions have a status. If a document consists of only one version – which is the case when creating a new document – the status of that version will also be the status of the document. If the document is created as a draft, the current version will also be a draft.
You maintain an overview of all versions of the document under the Versions tab.
Info: 
indicates that it is the current version of the document.
Why use versions of a document:
If changes have to be made to a published document, creating a new version as a draft is recommended. The document can then be fully prepared before it is published and put into use. The history of all versions of the document is also retained throughout the life of the document.
It is not possible to publish a historical version of a document. If a document's latest version has the status History but the document is to be published, you can create a new draft and publish the new version.
Info: It is the current version of the document that is available in relationships that the document has in other modules.