If “delete” really means “delete” to you, then you probably don’t just want to delete your iCloud account but wipe all iCloud files. Since iCloud is automatically linked to your Apple ID, you’ll also need to delete your Apple ID to move ahead. However, an Apple ID is necessary to use Apple services, and by deleting it, you will lose access to all Apple features and remove all stored data, contacts, and settings.
If this is what you want, follow these steps:
Step 1: Sign in on the Apple Privacy Homepage with your Apple ID.
Step 2: Under “Manage your data” select “Delete your account”.
Step 3: Select a reason for deleting your account and choose “Continue”.
Step 4: Provide a contact that Apple can send you deletion information to. This contact will provide you with the access code to request the deletion.
Step 5: Select “Delete account”. Deleting your Apple account can take up to 7 days.
Step 6: Next, delete your Apple ID from all your devices by going to “iTunes & App Store” and choosing “Sign out” in the settings.