Find first and last date of given week

date.php

<?php
// Get timestamp
$date_string = 'June 19, 2020';
$timestamp = strtotime( $date_string );

// Get weekday for given date
// Return 0-6 for Sun to Sat
$weekday = date( 'w', $timestamp );

// Calculate first and last date of given week
// 86400 = seconds in a day
$first_day = date( 'D, F j, Y', $timestamp - ( $weekday * 86400 ) );
$last_day = date( 'D, F j, Y', $timestamp + ( ( 6 - $weekday ) * 86400 ) );

echo $first_day . "\n";
echo $last_day . "\n";