Sub openf()
Dim FSO As Object
Dim fPath As String
Dim myFolder, myFile
Dim wdApp As Object
Dim wdDoc As Variant

fPath = "C:\" 'change to your directory
Set wdApp = GetObject(, "Word.Application")
Set FSO = CreateObject("Scripting.FileSystemObject")
Set myFolder = FSO.GetFolder(fPath).Files
For Each myFile In myFolder
If LCase(myFile) Like "*.docx" Then 'change to you file type
      Set wdDoc = wdApp.Documents.Open(CStr(myFile))
      wdApp.Visible = True
      FindAndReplaceFirstStoryOfEachType
      wdDoc.Save
      wdDoc.Close
      Set wdDoc = Nothing
End If
Next myFile

End Sub

Sub FindAndReplaceFirstStoryOfEachType()

If ActiveWindow.View.SplitSpecial <> wdPaneNone Then
    ActiveWindow.Panes(2).Close
End If
If ActiveWindow.ActivePane.View.Type = wdNormalView Or ActiveWindow. _
    ActivePane.View.Type = wdOutlineView Then
    ActiveWindow.ActivePane.View.Type = wdPrintView
End If
ActiveWindow.ActivePane.View.SeekView = wdSeekCurrentPageHeader
Selection.MoveRight Unit:=wdCharacter, Count:=14
Selection.MoveDown Unit:=wdLine, Count:=1
Selection.MoveRight Unit:=wdCharacter, Count:=3
Selection.MoveLeft Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.Delete Unit:=wdCharacter, Count:=1
Selection.TypeText Text:=Format(Now(), "dd/mm/yyyy")
Selection.MoveLeft Unit:=wdCharacter, Count:=4
Selection.TypeBackspace
Selection.TypeText Text:="/"
End Sub

Sub FindAndReplaceFirstStoryOfEachType()
Set objRegEx = CreateObject("vbscript.regexp")
objRegEx.Global = True
objRegEx.IgnoreCase = True
objRegEx.MultiLine = True
objRegEx.Pattern = "[0-9]{2}/[0-9]{2}/[0-9]{4}"

Dim rngStory As Range
For Each rngStory In ActiveDocument.StoryRanges
If Not IsEmpty(rngStory) Then
With rngStory.Find
    If objRegEx.test(rngStory) = True Then

     .Text = CStr(rngStory)
     .Replacement.Text = Format(now(), "mm/dd/yyyy")
     .Wrap = wdFindContinue
     .Execute Replace:=wdReplaceAll
    End If
End With

End If
Next rngStory
End Sub

ActiveDocument.ActiveWindow.ActivePane.View.SeekView = wdSeekCurrentPageHeader