Yes i have access to my cpanel.
The quota i talking about is the option to create webdisk so you can use your iPhone and computer to upload to that webdisk.
But if i give access they can fill up there web host space if they don´t control it well. So what i want to do is to be able to set how much space on the web disk they can use.
There's no quota support for web disk accounts. The quota is aligned with the disk space quota of the cPanel account. You could setup FTP accounts instead of Web Disk accounts if you wanted to allow specific users the ability to upload files while also imposing a quota on the individual account.