Dim filename As String
  Const FILEPATH As String = "\\SERVER\Billing\"
 
  filename = FILEPATH & Format(Date, "yyyymmdd") & "_" & [Mdid] & ".pdf"
  ' or
  filename = FILEPATH & [Mdid] & "_" & Format(Date, "yyyymmdd") & ".pdf"
  Debug.Print filename
 
  DoCmd.OutputTo acOutputReport, , acFormatPDF, filename