Send link in email with multiple QueryString parameter in ASP.Net

Dear Sir,

I want to send the url in email . it is working fine with single querystring  parameter.

how can i send multiple parameter. Please help me.

Single  Email Body 

EmailBody = "Dear Manager, " + "<br/>" + "<br/>" +
"Please approve order form as below. " + "<br/>" + "<br/>" +
"Order No : " + TmpDocumentNo + "<br/>" +
"Customer : " + TxtCustomerName.Text + "<br/>" +
"Model : " + TxtModelName.Text + "<br/>" +
"Transmission : " + TxtTransmission.Text + "<br/>" +
"Qty : " + TxtQty.Text + "<br/>" +
"Tax Apply : " + DdlTaxApply.SelectedItem.Text + "<br/>" +
"Net Amount (USD) : " + TxtNetPayable.Text + "<br/>" +
"Exchange Rate : " + TxtExchnageRate.Text + "<br/>" +
"Net Amount (GHS) : " + TxtNetPayableGhs.Text + "<br/>" + "<br/>" +
"Please click the following link to approve." + "<br/>" +
"<a href = '" + Request.Url.AbsoluteUri.Replace("OrderFormSales.aspx", "OrderFormSalesApprovalOnline.aspx?Id=" + TmpDocumentNo) + "'>Click here for Approve</a>." + "<br/>" +
"Thanks & Regards " + "<br/>" +
TxtUserName.Text.ToUpper() + "<br/>" +
TxtUserBranchName.Text.ToUpper() + "<br/>" +
TxtUserEmailId.Text.ToUpper();

Querystring retrive

protected void Page_Load(object sender, EventArgs e)
{
    if (!string.IsNullOrEmpty(Request.QueryString.ToString()))
    {
        //--- We can get value of query string by passing name of query string or by passing its index
        string a = Request.QueryString["Id"].ToString();Label1.Text = a.ToString();
    }
}