Comment coder ça

Private Sub CommandButton1_Click()
Dim i As Integer
    With Worksheets("Feuil1")   'ADAPTER le nom de la feuille
        For i = 45 To 5000  'boucle sur les cellules D45:D5000 ADAPTER le 45 et le 5000 de la boucle
            If .Range("D" & i).Value = "F" Then .Range("C" & i).ClearContents
        Next
    End With
End Sub

 Private Sub Worksheet_Change(ByVal Target As Range)
    If Target.Cells.Count = 1 Then
        If Not Intersect(Target, Range("D45:D5000")) Is Nothing Then
            If Target.Value = "F" Then Target.Offset(, -1).ClearContents
        End If
    End If
End Sub