To use this, like this example: https://stackoverflow.com/questions/55521974/how-to-open-the-native-ios-share-modal-from-a-link-on-a-webpage/55652958
You MUST NOT call this function directly from your Velo code editor, please use “Custom Code (HTML)” under your dashboard (Premium Site), Settings > Custom code.
To get the custom code function triggered, please see: https://www.wix.com/velo/reference/wix-window/postmessage