StoryMaps is a multimedia web content platform hosted by Esri’s ArcGIS Online. StoryMaps are designed to work with the map content of ArcGIS Online, but you can also create a StoryMap without any maps at all. The site will allow you to create an interactive website with text, images and video clips (as well as custom maps). The StoryMaps tool is available to anyone with an ArcGIS Online Account.
You can access StoryMaps directly from the StoryMaps site if you already have an ArcGIS Online.
Or, from within ArcGIS Online, you can choose the StoryMaps option under Content > Create App.