Copy the below code and do right click on Home sheet tab and select view code and paste it.
Close the VBA window (Alt+Q to close VBA window) and return to that sheet and check.
Private Sub Worksheet_Change(ByVal Target As Range)
With ThisWorkbook.Worksheets("Audit Trail")
Dim iCol As Integer, lRw As Long
iCol = .Cells(1, .Columns.Count).End(xlToLeft).Column
lRw = .Cells(.Rows.Count, iCol).End(xlUp).Row
If lRw = .Rows.Count - 1 Then
.Cells(lRw + 1, iCol).Value = "--x--"
iCol = iCol + 1
lRw = 0
End If
.Cells(lRw + 1, iCol).Value = Target.Address(0, 0)
End With
End Sub
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