How to convert EML or MSG to PDF with attachment and cover page?

using MsgReader;
using System.IO;
using Syncfusion.HtmlConverter;
using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Pdf.Interactive;

//Convert EML or MSG to HTML using third party reader
var msgReader = new Reader();
string tempFolder = Path.GetTempPath();
 
//File contains the HTML file converted from MSG
var files = msgReader.ExtractToFolder(filePath, tempFolder);
var error = msgReader.GetErrorMessage();
 
if (!string.IsNullOrEmpty(error))
    throw new Exception(error);
 
//Converts the HTML to PDF using Blink rendering engine
if (!string.IsNullOrEmpty(files[0]))
{
    //Initialize HTML to PDF converter
    HtmlToPdfConverter htmlConverter = new HtmlToPdfConverter();
    
    //Convert HTML to PDF document
    PdfDocument document = htmlConverter.Convert(files[0]);
 
    if (checkBox1.Checked)
    {
        //Add cover page
        PdfPage coverPage = new PdfPage();
 
        //Insert page 
        document.Pages.Insert(0, coverPage);
        
        //Draw text in cover page 
        PdfFont font = new PdfTrueTypeFont(new Font("Helvetica", 16, FontStyle.Bold), true);
        PdfSolidBrush brush = new PdfSolidBrush(Color.FromArgb(44, 71, 120));
        coverPage.Graphics.DrawString("cover page", font, brush, new PointF());
    }
    if (checkBox2.Checked)
    {
        //Insert attachments
        for (int i = 1; i < files.Length; i++)
        {
            FileInfo file = new FileInfo(files[i]);
            document.Attachments.Add(AddAttachment(file));
        }
    }
    
    //Save and close the document
    document.Save("Output.pdf");
    document.Close(true);
 
    //Message box confirmation to view the created PDF document
    if (MessageBox.Show("Do you want to view the PDF file?", "PDF File Created",
        MessageBoxButtons.YesNo, MessageBoxIcon.Information)
        == DialogResult.Yes)
    {
        //Launching the PDF file using the default Application.[Acrobat Reader]
        System.Diagnostics.Process.Start("Output.pdf");
        this.Close();
    }
    else
    {
        // Exit
        this.Close();
    }
}

private PdfAttachment AddAttachment(FileInfo f)
{
    //Create attachment 
    PdfAttachment attachment = new PdfAttachment(f.FullName);
    attachment.ModificationDate = DateTime.Now;
    attachment.Description = f.Name;
    attachment.MimeType = "application/" + f.Extension;
 
    //Returns the attachment to the document
    return attachment;
}