php random number generator

function generateRandomString($length = 25) {
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $charactersLength = strlen($characters);
    $randomString = '';
    for ($i = 0; $i < $length; $i++) {
        $randomString .= $characters[rand(0, $charactersLength - 1)];
    }
    return $randomString;
}
//usage 
$myRandomString = generateRandomString(5);

you can use rand() function for that in php.
Example:
Generate random numbers between 1 to 50
<?php
  echo rand(1,50);
?>

// $min and $max are optional
rand($min,$max);

rand(0,10);
or
random_int(0,10)

<?php
  echo rand(1,50);
?>

rand();