With an active iCloud account, Notebooks can store your documents on iCloud and automatically synchronize them to all connected devices. When set up this way, Notebooks uses a predefined folder on iCloud Drive (iCloud Drive/Notebooks), so you should not create that folder yourself. – It is not necessary to purchase the optional Custom Storage Location option, either, as the option to use iCloud is available to all users of Notebooks 11 or later.
You find all details about iCloud sync and moving your documents to iCloud in a dedicated chapter.
Synchronize Through iCloud Drive