Sub UpdateBookmarks()

Dim bmInput As String

For Each bm In ActiveDocument.Bookmarks
    bmInput = InputBox("Please enter " & bm.Name)
    UpdateBM ActiveDocument, bm.Name, bmInput
Next

End Sub

Sub UpdateBM(ByRef bmDoc As Document, bmName As String, bmContent As String)
Dim bmRng As Word.Range
    Set bmRng = bmDoc.Bookmarks(bmName).Range
    bmRng.Text = bmContent
End Sub

Sub UpdateBookmarks()
Dim lngIndex As Long
Dim oRng As Range
Dim strName As String
  With ActiveDocument
    For lngIndex = 1 To .Bookmarks.Count
      Set oRng = .Bookmarks(lngIndex).Range
      strName = .Bookmarks(lngIndex).Name
      oRng.Text = InputBox("Please enter " & strName)
      .Bookmarks.Add strName, oRng
    Next
  End With
lbl_Exit:
  Exit Sub
End Sub

Sub UpdateBookmarks()
Dim i As Long
With ActiveDocument
  For i = 1 To .Bookmarks.Count
    With .Bookmarks(i)
      Call UpdateBM(.Name, InputBox("Please enter " & .Name))
    End With
  Next
End With
End Sub

Sub UpdateBM(bmName As String, bmContent As String)
Dim bmRng As Word.Range
With ActiveDocument
  Set bmRng = .Bookmarks(bmName).Range
  bmRng.Text = bmContent
  .Bookmarks.Add bmName, bmRng
End With
End Sub

Sub UpdateBookmarks()
Dim lngIndex As Long, lngPart As Long
Dim oRng As Range
Dim strName As String, strDisplay As String
Dim arrParts() As String
  With ActiveDocument
    For lngIndex = 1 To .Bookmarks.Count
      Set oRng = .Bookmarks(lngIndex).Range
      strName = .Bookmarks(lngIndex).Name
      arrParts = Split(strName, "_")
      If UBound(arrParts) > 0 Then
        'For processing bookmarks names using following convention: _
         A_Complany_Name, B_Company_Address, etc.
        strDisplay = vbNullString
        For lngPart = 1 To UBound(arrParts)
          strDisplay = strDisplay & " " & arrParts(lngPart)
        Next
        oRng.Text = InputBox("Please enter " & strDisplay)
      Else
        oRng.Text = InputBox("Please enter " & strName)
      End If
      .Bookmarks.Add strName, oRng
    Next
  End With
lbl_Exit:
  Exit Sub
End Sub