Is this a real warning from Apple?

Some related and quick reading on some of the common scams:

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

How?

malakhi25 wrote:

How?

If you’re somehow stuck in Safari, quit the app, Settings > Safari > Advanced > Website Data > Remove All Website Data, and then re-launch Safari.

If it’s Mail, delete it.

If it’s phone spam, hang up.

If it’s a message, delete it.

It's spam.

Delete it.