when i am sharing the XD file with developer and he is not getting the download option for the icon and I have installed the the plugin from where i have used it however he is getting the download option when i a using the icon from other source.
If I understand the situation correctly, that icon (or whatever element it is) is probably being converted into an image, and this is what a developer might be able to download. But you do need to switch on that Mark for Export option in the Layers panel.
If that option isn't available to the element, then it's because the plug-in might be preventing it (or simply doesn't comply with this feature). Which plug-in and icon repository are you using ?