<?php
function diffDatesArray($from, $to, $formatInput, $formatOutput) {
    $out = [];
    $fromDate = DateTime::createFromFormat($formatInput, $from);
    $toDate = DateTime::createFromFormat($formatInput, $to);
    $interval = date_diff($fromDate, $toDate);
    $daysInterval = intval($interval->format('%d'));
    for ($i = 0; $i <= $daysInterval; $i++) {
        $nextDay = clone $fromDate;
        if($i >= 1){
            $nextDay->modify('+'.$i.' day');
        }
        $out[] = $nextDay->format($formatOutput);
    }
    return $out;
}
$datesArray = diffDatesArray('20/03/2019', '3/04/2019', 'd/m/Y', 'd/m/Y');
print_r($datesArray);
?>