It's a common question, so what exactly is a cloud service you need to list within the Self-Assessment and subsequently have tested in a Plus Assessment.
The quick answer is: "A cloud service is where the applicant subscribes to a (paid or free) service, and controls who has access and/or administrative access over the cloud service."
For example: Microsoft 365/Azure, Google Cloud/GSuite, Amazon Web Services (AWS), QuickBooks, Dropbox, Ciphr HR, Salesforce etc
Within Cyber Essentials, data classification isn't relevant, therefore we are not concerned with what data is within a cloud service, if its used in the business, its in scope for Cyber Essentials.