How can I delete an iCloud account?

Re: I have a Gmail account and I mistakenly created an iCloud account.

Please I want to delete the iCloud account : Help me : I need solution

You may have begun using some of the free 5Gb in iCloud, or you may have begun a monthly subscription plan?

Your Apple (ID) Account is the one account you use to access Apple services like the App Store, Apple Music, iCloud, iMessage, FaceTime, and more.

It includes the email address and password you use to sign in as well as the contact, payment, and security details you use across Apple services.

Apple computer and device users have a free 5 Gb available in iCloud.

Eg: You can turn off sync of Mail data to iCloud if you wish ... there's nothing to cancel

Change which apps sync and store data with iCloud - Apple Support

Eg: says:

On your iPhone, iPad, or Apple Vision Pro

1. Go to Settings > your name.
2. Tap iCloud.
3. Tap See All next to Saved to iCloud.
4. Tap an app to choose whether to sync or use it with your device or not.

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Else: If you mistakenly took out a subscription to iCloud + which provides more storage at a monthly cost

You can cancel the subscription, or downgrade to free 5Gb:

See how to: Downgrade or cancel your iCloud+ plan - Apple Support

If you paid $ : you can try: Request a refund for apps or content that you bought from Apple - Apple Support