Create and split word document into two columns in ASP.Net

Good day,

I merged document file using the following code which was successfull.

Please how can split it into two columns as in book form? Such that it will have two columns left and right with a vertical line at the center of each page (Divid each page into two columns with a vertical line at the center).

Thnk you.

    Dim missing As Object = System.Type.Missing
    Dim pageBreak As Object = Microsoft.Office.Interop.Word.WdBreakType.wdSectionBreakNextPage
    Dim outputFile As Object = outputFilename
    Dim wordApplication As Microsoft.Office.Interop.Word._Application = New Microsoft.Office.Interop.Word.Application()
    Try
        Dim wordDocument As Microsoft.Office.Interop.Word.Document = wordApplication.Documents.Add(missing, missing, missing, missing)
        Dim selection As Microsoft.Office.Interop.Word.Selection = wordApplication.Selection
        Dim documentCount As Integer = filesToMerge.Length
        Dim breakStop As Integer = 0
        For Each file As String In filesToMerge
            breakStop += 1
            selection.InsertFile(file, missing, missing, missing, missing)
  
            If insertPageBreaks AndAlso breakStop <> documentCount Then
                selection.InsertBreak(pageBreak)
            End If
        Next
        wordDocument.SaveAs(outputFile, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing)
        wordDocument = Nothing
    Catch ex As Exception
        Throw ex
    Finally
        wordApplication.Quit(missing, missing, missing)
    End Try