why i cant mkdir in 00webhostapp php code example

Example 1: php mkdir

// Create a directory with the permission level (optional)
<?php
mkdir("/path/to/my/dir", 0700);
?>

Example 2: php mkdir recursive

<?php
// Create a directory recursively (make sure to sanitize if taken from input as always!)
mkdir("/path/to/my/dir", 0777, true);