Send html page as email body in ASP.Net

 protected void send_mail()
    {
        String genpass;
        genpass = GeneratePassword();
        lblResult.Text = genpass.ToString();
        
        string mail_id = "xtream.hell97@gmail.com";
        string mail_password = "XXXXXXX";

        MailMessage msg = new MailMessage();
        msg.From = new MailAddress(mail_id, "Apiit Library");
        msg.To.Add(new MailAddress(txt_email.Text));
        msg.Subject = "Password Information Of LMS";
        msg.Body = "Your password is" + ": " + genpass;

        msg.IsBodyHtml = true;

        SmtpClient smtp = new SmtpClient();
        smtp.Host = "smtp.gmail.com";
        smtp.Credentials = new NetworkCredential(mail_id, mail_password);

        smtp.EnableSsl = true;
        try
        {
            
            smtp.Send(msg);
            create_user_query(genpass);
            lblResult.Text = "Email send successfully:";
        }
        catch (Exception ex)
        {
            lblResult.Text = ex.Message;
        }
    }

    private string GeneratePassword()
    {
        string strPwdchar = "abcdefghijklmnopqrstuvwxyz0123456789#+@&$ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        string strPwd = "";
        Random rnd = new Random();
        for (int i = 0; i <= 7; i++)
        {
            int iRandom = rnd.Next(0, strPwdchar.Length - 1);
            strPwd += strPwdchar.Substring(iRandom, 1);
        }
        return strPwd;
    }

i want to send this email in formated html with logo. So i want to chane only its body part with html page to send users auto generated password.