Load from URL

public static void LoadDocumentFromUrl()
{
    string url = "https://github.com/groupdocs-viewer/GroupDocs.Viewer-for-.NET/blob/master/Examples/Resources/SampleFiles/sample.docx?raw=true";
    
    Stream stream = DownloadFile(url);

    using (Viewer viewer = new Viewer(stream))
    {
        HtmlViewOptions viewOptions = HtmlViewOptions.ForEmbeddedResources();                
        viewer.View(viewOptions);
    }
}
        
static Stream DownloadFile(string url)
{
    WebRequest request = WebRequest.Create(url);
    using (WebResponse response = request.GetResponse())
        return GetFileStream(response);
}

static Stream GetFileStream(WebResponse response)
{
    MemoryStream fileStream = new MemoryStream();
    using (Stream responseStream = response.GetResponseStream())
        responseStream.CopyTo(fileStream);
    fileStream.Position = 0;
    return fileStream;
}