I create a WordTemplate with some placeholders for field,in code I insert value in this placeholders and show it to user.

protected void Button1_Click(object sender, EventArgs e)
    {
        string DocFilePath = "";
        //string FilePath = System.Windows.Forms.Application.StartupPath;
        object fileName = @"[...]\asset\word templates\FormatPeygiri1.dot";
        DocFilePath = fileName.ToString();

        FileInfo fi = new FileInfo(DocFilePath);
        if (fi.Exists)
        {
            object readOnly = false;
            object isVisible = true;

            object PaperNO = "PaperNO";
            object PaperDate = "PaperDate";
            object Peyvast = "Peyvast";

            object To = "To";
            object ShoName = "ShoName";
            object DateName = "DateName";

            Microsoft.Office.Interop.Word.Document aDoc = WordApp.Documents.Open(ref fileName, ref missing, ref readOnly,
               ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing,
               ref isVisible, ref isVisible, ref missing, ref missing, ref missing);

            WordApp.ActiveDocument.FormFields.get_Item(ref PaperNO).Result = TextBox_PaperNO.Text;

            string strPaperDate = string.Format("{0}/{1}/{2}", PersianDateTimeHelper.GetPersainDay(DateTimePicker_PaperDate.SelectedDate),
                                               PersianDateTimeHelper.GetPersainMonth(DateTimePicker_PaperDate.SelectedDate),
                                               PersianDateTimeHelper.GetPersainYear(DateTimePicker_PaperDate.SelectedDate));

            WordApp.ActiveDocument.FormFields.get_Item(ref PaperDate).Result = strPaperDate;

            WordApp.ActiveDocument.FormFields.get_Item(ref Peyvast).Result = TextBox_Peyvast.Text;

            WordApp.ActiveDocument.FormFields.get_Item(ref To).Result = TextBox_To.Text; ;
            WordApp.ActiveDocument.FormFields.get_Item(ref ShoName).Result = TextBox_ShoName.Text;

            string strDateName = string.Format("{0}/{1}/{2}", PersianDateTimeHelper.GetPersainDay(DateTimePicker_DateName.SelectedDate),
                                               PersianDateTimeHelper.GetPersainMonth(DateTimePicker_DateName.SelectedDate),
                                               PersianDateTimeHelper.GetPersainYear(DateTimePicker_DateName.SelectedDate));

            WordApp.ActiveDocument.FormFields.get_Item(ref DateName).Result = strDateName;

            aDoc.Activate();
            WordApp.Visible = true;
            aDoc = null;
            WordApp = null;
        }
        else
        {
            MessageBox1.Show("File Not Exist!");
        }

it work good and successfully! but when a user close the Word,her Process not closed and exists in Task Manager Process list. this process name is WINWORD.exe I know that I can close process whit code [process.Kill()] but I don't know which process that I should to kill. if I want to kill all process with name [WINWORD.exe] all Word window closed.but I want to close specific Word window and kill process that I opened.

How to do it?