The standard publication process consists of content creation, review and publication. It also allows you to configure the item to be deleted or expired on a certain date. An expired item's status is no longer Live, but it is preserved in the database.
Each content item goes through either the standard publication process or a custom approval work flow created by your Website Administrator. Both are formalized steps to be performed by different individual users. The custom approval work flow requires items to be reviewed by one or more experts before it can be published. For example, you can require a page be reviewed by counsel for legal issues before it is published.
Custom work flows can be assigned to a single item or as the default for a content type (in other words, for all items of that type).