RobiNew
You would have gotten a compact expert answer from any one of the contributors here had you posted your entire code snippet from the start.
I would suggest you change your use of font.superscript to the style method as Paul suggested. Also, with the code you have now, you could create a colossal mess if you need to edit the document to create additional footnotes or the code is inadvertently run again on the document.
Code:
Option Explicit
Sub AddSufficToFootnoteRef()
Dim ftNote As Footnote
Dim supLetter As String
Dim bSkip As Boolean
supLetter = "a"
For Each ftNote In ActiveDocument.Footnotes
bSkip = True
With ftNote.Range
If Not .Characters.First = supLetter Then
bSkip = False
.Characters.First.Previous = supLetter & " "
.Characters.First.Style = wdStyleFootnoteReference
End If
End With
If Not bSkip Then
With ftNote.Reference
.Characters.Last.InsertAfter supLetter
.Characters.Last.Next.Style = wdStyleFootnoteReference
End With
End If
Next
lbl_Exit:
Exit Sub
End Sub
Sub InsertFootnote()
'Create a new suffixed footnote
Dim oFN As Footnote
Dim supLetter As String
supLetter = "a"
Application.Dialogs(wdDialogInsertFootnote).Execute
Set oFN = Selection.Footnotes(1)
With oFN.Range
.Characters.First.Previous = supLetter & " "
.Characters.First.Style = wdStyleFootnoteReference
End With
With oFN.Reference
.Characters.Last.InsertAfter supLetter
.Characters.Last.Next.Style = wdStyleFootnoteReference
End With
oFN.Range.Select
Selection.Collapse wdCollapseEnd
lbl_Exit:
Exit Sub
End Sub