Arcgis viewer for flex
You may want to look at this thread can anyone send me the link of arcgis api for flex plz
how to publish an Arcgis Viewer for Flex application on the internet for everyone to see
Because many of the modern browsers no longer support Flash and Flex, you most likely will not be able to get "everyone to see". You should instead look at Web AppBuilder for ArcGIS (Developer Edition) | ArcGIS for Developers which is basically the JavaScript version of the older Flex Viewer
There is an active community for https://community.esri.com/groups/web-app-builder-custom-widgets?sr=search&searchId=dd47e368-5a44-49...
And I have several blogs to help you get started /blogs/myAlaskaGIS/2015/01/15/tips-and-observations-for-getting-web-appbuilder-developer-edition-ins...
So, I know this doesn't answer your question the way you would like, but I think the answer is you will not be able to get a Flex app to work for most people anymore unless you limit which browser they are allowed to use.
Hi Ricardo,
FYI, the ArcGIS Viewer for Flex is no longer supported by Esri. It was retired in June 2016. Please see the product life cycle doc: http://downloads.esri.com/support/product%20life%20cycle/online_gis/ArcGISWebMappingAPIs_PLC.pdf
To answer your specific question, please see this help topic,
Deploying an application—ArcGIS API for Flex | ArcGIS for Developers
But I would suggest you follow Rebecca's comments above and migrate to Web AppBuilder for ArcGIS which uses the latest technology advances.
Hope this helps,