Here is some sample code that you can probably adapt to suit your needs:

Public Sub FindReplaceAnywhere()
Dim rngStory As Word.Range
Dim pFindTxt As String
Dim pReplaceTxt As String
Dim lngJunk As Long
Dim oShp As Shape

pFindTxt = InputBox("Enter the text that you want to find.", _
"FIND")
If pFindTxt = "" Then
 MsgBox "Cancelled by User"
 Exit Sub
End If
Tryagain:
pReplaceTxt = InputBox("Enter the replacement.", "REPLACE")
If pReplaceTxt = "" Then
 If MsgBox("Do you just want to delete the found text?", vbYesNoCancel) =
vbNo Then
   GoTo Tryagain
 ElseIf vbCancel Then
   MsgBox "Cancelled by User."
   Exit Sub
 End If
End If
'Fix the skipped blank Header/Footer problem
lngJunk = ActiveDocument.Sections(1).Headers(1).Range.StoryType
ResetFRParameters
'Iterate through all story types in the current document
For Each rngStory In ActiveDocument.StoryRanges
 'Iterate through all linked stories
 Do
   SrcAndRplInStory rngStory, pFindTxt, pReplaceTxt
   On Error Resume Next
   Select Case rngStory.StoryType
     Case 6, 7, 8, 9, 10, 11
       If rngStory.ShapeRange.Count > 0 Then
         For Each oShp In rngStory.ShapeRange
           If oShp.TextFrame.HasText Then
             SrcAndRplInStory oShp.TextFrame.TextRange, _
               pFindTxt, pReplaceTxt
           End If
         Next
       End If
     Case Else
       'Do Nothing
   End Select
   On Error GoTo 0
   'Get next linked story (if any)
   Set rngStory = rngStory.NextStoryRange
 Loop Until rngStory Is Nothing
Next
End Sub
Public Sub SrcAndRplInStory(ByVal rngStory As Word.Range, _
ByVal strSearch As String, _
ByVal strReplace As String)
With rngStory.Find
 .ClearFormatting
 .Replacement.ClearFormatting
 .Text = strSearch
 .Replacement.Text = strReplace
 .Execute Replace:=wdReplaceAll
End With
End Sub
Sub ResetFRParameters()
With Selection.Find
 .ClearFormatting
 .Replacement.ClearFormatting
 .Text = ""
 .Replacement.Text = ""
 .Forward = True
 .Wrap = wdFindContinue
 .Format = False
 .MatchCase = False
 .MatchWholeWord = False
 .MatchWildcards = False
 .MatchSoundsLike = False
 .MatchAllWordForms = False
 .Execute
End With
End Sub