Use of Range.Characters

If you want to highlight Character which meet with your Criteria , You can use the Below Code :

Sub HighLight()

Application.ScreenUpdating = False

On Error Resume Next

    Dim cell As Range

    Dim rng As Range

    Dim st As String

    Dim loc As Integer

Dim n as string

    st = ""

        Set rng = ActiveSheet.UsedRange

            For Each cell In rng

                If cell.Value <> "" Then

                    st = st & cell.Value

                End If

            Next

           

                For i = 1 To Len(st)

                    n = Mid(st, i, 1) & Mid(st, i + 1, 1) & Mid(st, i + 2, 1)

                    If Asc(Mid(n, 1, 1)) > 64 And Asc(Mid(n, 1, 1)) < 91 And Asc(Mid(n, 2, 1)) > 64 And Asc(Mid(n, 2, 1)) < 91 And Asc(Mid(n, 3, 1)) > 64 And Asc(Mid(n, 3, 1)) < 91 Then

                    

                           

                            Cells.Find(What:=n, After:=ActiveCell, LookIn:=xlFormulas, LookAt:= _

                            xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=True _

                            , SearchFormat:=False).Activate

                            loc = WorksheetFunction.Find(n, ActiveCell.Value, 1)

                    ActiveCell.Characters(loc, 3).Font.ColorIndex = 26

                    ActiveCell.Characters(loc, 3).Font.Bold = True

                    i = i + 3

                     End If

                Next

               

                Application.ScreenUpdating = True

               

End Sub