What differences exist in changing permissions for manually created folders versus folders created using mkdir() in PHP scripts?

When manually creating folders on a server, the default permissions are typically set by the system. However, when using the mkdir() function in PHP scripts to create folders, the permissions may need to be explicitly set using the chmod() function to ensure the desired access levels. To change permissions for folders created using mkdir() in PHP scripts, you can use the chmod() function with the appropriate permissions specified.

// Create a new directory
$dir = 'new_folder';
mkdir($dir);

// Set permissions for the new directory
chmod($dir, 0755);