Filing system

You need a worksheet change macro
This macro adds date when a C is entered into column A - Change the red number 1 as required

'These instructions pre typed & are worded to cater for the novice programmer
'To install macro to correct location

'Copy this macro
'GoTo Excel
'Select sheet this is to appy to
'Right Click on Sheet Name Tab > select View Code
'Past macro into the Worksheet Module displayed

Private Sub Worksheet_Change(ByVal Target As Range)
   If Target.Column = 1 Then
      If UCase(Target) = "C" Then
         Application.EnableEvents = False
         With Target
            .Value = Now()
            .NumberFormat = "yymmdd"
         End With
      End If
   End If
   Application.EnableEvents = True
End Sub

One of the commands in the macro turns off event triggers - if this command is run & for some reason the command tha turns them back on does not get run when you type the C in nothing happens.

Place this macro on the same module sheet

Sub ReActivateEvents()
Application.EnableEvents = True
End Sub

Run it (F5)
Try your sheet