The file when saved in .bmp format can be opened in windows.
var pdfDocument = new PdfDocument(url);
var page = pdfDocument.Pages[pgNo];
var pageBitmap = new PDFiumBitmap(2000, 2800, true);
page.Render(pageBitmap, PageOrientations.Normal);
pageBitmap.Save(Application.persistentDataPath + @"\Test.bmp", 300, 300);