Laravel 8 Datumsformat
// in model
protected $casts = [
'date_of_approval' => 'date:d-m-Y'
];
// if you want change format any where
$appointment->date_of_approval->format('Y-m-d');
// if you have not cast in model data format
Carbon\Carbon::parse($appointment->date_of_approval)->format('Y-m-d');
Naveed Shahzad