I need assistance with a sharing feature/button inside an app: when you press the share button, a picture of the app with a short description should automatically be copied into the post before sharing it to Facebook for users to download the app.

[Andrey KupreevKeymaster]

a

After you made the settings you need  in share options in this button  & saved the changes,

pressing Share on the device you should first choose Email option (as address) before  post to Facebook.