public static void AddComment() { WordDocument document = new WordDocument(); WordDocumentBuilder builder = new WordDocumentBuilder(document); builder.InsertLine("First paragraph in this document."); //Insert some content before comment builder.InsertText("Second paragraph start. "); //Select the content you want to comment TextInline textComment = builder.InsertText("Text has comment. "); //Insert some content after comment builder.InsertText("Second paragraph end."); //Add comment with selected content Comment comment = builder.InsertComment("Comment details here", textComment, textComment); comment.Author = "iDiTect"; comment.Date = DateTime.Now; WordFile wordFile = new WordFile(); using (var stream = File.OpenWrite("AddComment.docx")) { wordFile.Export(document, stream); } }