Sub SrikeAllHighlightText()
' Paul Beverley - Version 25.10.20
' Adds strikethrough to all highlighted text

Set rng = ActiveDocument.Content
With rng.Find
  .ClearFormatting
  .Replacement.ClearFormatting
  .Text = ""
  .Highlight = True
  .Wrap = wdFindStop
  .Replacement.Text = ""
  .Forward = True
  .MatchWildcards = False
  .Execute
End With

myCount = 0
Do While rng.Find.Found = True
' If you want to count them...
' Note where the end of the found item is
  endNow = rng.End
  rng.Font.StrikeThrough = True
  
  ' Be sure you're past the previous occurrence
  rng.Start = endNow
  rng.End = endNow

' Go and find the next occurrence (if there is one)
  rng.Find.Execute
Loop

End Sub