Okay imagine this a April Month so I want all the days in April. like-> [ Apr 1, Apr 2, ......., Apr 30]

$period  = CarbonPeriod::create(Carbon::now()->firstOfMonth(), Carbon::now()->lastOfMonth());

//For formatted view, you can show any type of format view like ('Y-m-d'), etc.
$dates = [];
foreach ($period as $date) {
    $dates[] = $date->format('M, d');
}

// Or you don't need custom format you can show the carbon format date,
$notFormatDays = $period->toArray();