I just got a notice that my iPhone 11 had been hacked. Phishing or real? How would I run a scan?

Almost certainly phishing.

Scams (e-mail, text messages, and phone calls) are getting very good at closely imitating true Apple communications. Always be cautious. Here are some guidelines:

Identifying legitimate emails from the iTunes Store - http://support.apple.com/HT201679 - lacking in specifics, the next link is better:

Recognize and avoid phishing messages, phony support calls, and other scams - https://support.apple.com/HT204759