Check Date Format Input into Excel Column with VBA code ("DD/MM/YYYY" format)

So, you didn't know how to adjust...

Change any cell(s) in Col.A, B

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim r As Range
    If Not Target.Column Like "[23]" Then Exit Sub
    If Target.Row < 3 Then Exit Sub
    Application.EnableEvents = False
    With CreateObject("VBScript.RegExp")
        .Pattern = "^(0[1-9]|[12][0-9]|3[01])/(0[1-9]|1[0-2])/\d{4}$"
        For Each r In Intersect(Target, Columns("b:c"))
            If Len(Target.Text) Then
                If (.test(r.Text) * IsDate(r.Text)) = 0 Then
                    MsgBox "Invalid date", , r.Text & " " & r.Address(0, 0)
                    r.ClearContents
                End If
            End If
        Next
    End With
    Application.EnableEvents = True
End Sub