The crowdsource story map recently was moved to mature status and is no longer supported. I have been receiving inquiries from educators who still want to use it and because of its ease of set up and simple interface, ask me if it is possible. Yes, at the present time, it is possible. However, it is not advised for high profile or large projects; for these projects, it is better to gather the data with Survey123 and make a map of the results or to use another crowdsource option listed here. I typically use this as an introductory activity in a face to face or online course or workshop, to have people share the landscape where they work, so we can discuss spatial patterns or landforms and vegetation type, to help them to start thinking spatially, and to get them immersed right away in web GIS technology.
If you still want to make a crowdsource story map, go to this location--the metadata page for the app:
Technical note: When I sign in to ArcGIS Online and I go to the above location, I typically do not see the "Create a Web App" choice. I know right away that I am in a loop where I cannot be signed in to ArcGIS Online and viewing the above page at the same time. What I have to do to get around this issue is to sign in to ArcGIS Online, and then search for “crowdsource story map app mature". Then, I go to the resulting page, and am now signed in, and ready to create my map, using "Create a Web App" as shown below.