This message is to inform you that your Apple Account ... has been temporarily locked until you can validate your Apple ID details on file. This is a security measure to protect your iCloud Account from unapproved use. We apologise for the inconvenience.

That or its ilk is the classic start of virtually every phishing attempt coming down the pipe/pike. Usually it's "from" a bank or email service.

In case it isn't obvious, you should delete tout de suite all such e-messages as your only response to same ... or be beholden to some Nigerian prince. tongue smirk

Under any doubtful circumstances a call to Apple or to your bank or email service provider should dispel lingering doubts. (Just be prepared to get in a queue. Bring a comforting beverage.)