Try this One..
Code:
Public Sub InsertColumns()
    
    Dim intCol As Integer

    Const strCol = "N:N" 'Here Just add the last Columns charactor Like "C:N"'s - N:N
    Const strSheetName = "Sheet1" ''Here just add the sheet Name
    Const intTotal = 5 'Here Pass the number of columns that you want to add
    
    With ThisWorkbook.Worksheets(strSheetName)
        For intCol = 1 To intTotal
            .Columns(strCol).Insert xlRight
        Next
    End With
    
End Sub


Regards
Prince