To create a folder on the server partition, use the PHP command: mkdir ();
In the example below, I will create a folder where your name will be the current system date.
<php $folder = date("Ymd");mkdir ($folder, 0755); ?>
The value "0755", will be allowed to read / write the new folder.
For dedicated servers, you can use 777.
To host servers / cpanel, you should use the permission to 755.