Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Range("F:F")) Is Nothing And Left(Target.Value, 3) <> "PRI" Then
Target.Value = "PRI" & Target.Value
End If
End Sub
1.Selects the cells you want:
2.Right click and choose Format Cells
3. Choose Custom
4. In the dialog box where you see Type below there in the line enter:PRI
I have only basic knowledge of Formulas and Codes.
=IF(ISTEXT(A1),"PRI"&A1)