I'm not 100% sure it's possible to do this without some creativity....but there are business partners that do this that are integrated with the platform. GeoDecisions Notify application comes to mind.
Thanks for your reply. I was thinking of something out-of-the-box, something ready to be set if needed, for occasional use, for small groups. I have take a look on geodecisions.com and looks great, but clearly it is a professional solution, aimed at communication for a large number of people.
Hi Luis - There is a way to send notifications using a geoprocessing server and then consuming it into AGOL via a gp widget in Web AppBuilder. Here is a mosquito solution that explains how to do it. I'd imagine you could set this up along with the power of geoevent to send automatic notifications. I'll be looking into this GP tool over the next couple days, in case you want to as well.
The 9-1-1 call center I contract to uses Vesta Alert from Cassidian Communications; it's built on top of ArcGIS Online and uses ArcGIS Server data I push.
