If a customer cannot save a document in iCloud, what should they check in settings?

When a customer is unable to save a document in iCloud, the key aspect to check in settings is iCloud Drive. This feature is specifically designed to store and manage files in iCloud. If iCloud Drive is turned off or not properly set up, the user will not be able to save documents or access them from various devices. Ensuring that iCloud Drive is enabled allows the user to save, retrieve, and share documents effectively across all their devices.

While other choices may have relevance in different contexts (such as iCloud Backup, which is more about backing up device data, or iCloud Storage, which deals with the available space), the functionality directly linked to saving documents lies within iCloud Drive. Checking iCloud Drive is the most direct approach for resolving issues related to saving documents, making it the appropriate option in this situation.