I have been told my email account may have been hacked

Read this document if you think your Apple ID has been compromised. --> If you think your Apple ID has been compromised - Apple Support

For iOS 15 or earlier, if you want to see if anyone else has access to your device or accounts, click here --> See who has access to your iPhone or iPad - Apple Support

For iOS 16 or later see how Safety Check on iPhone works to keep you safe. How Safety Check on iPhone works to keep you safe - Apple Support

Related materials:

Personal Safety User Guide

Personal Safety User Guide - Apple Support

> open the Table of Contents and review the articles

A document with general information about security and your Apple ID --> Security and your Apple ID - Apple Support

Contact Apple for help with Apple ID account security by clicking on this link --> Contact Apple for help with Apple ID account security - Apple Support "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues."

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Note that fake warning messages are very common as part of scams, particularly if you see them as browser popups. Scams (e-mail, text messages, and phone calls) are getting very good at closely imitating true Apple communications. Always be cautious. These support articles have some guidelines:

About identifying legitimate emails from the App Store and iTunes Store --> Identify legitimate emails from the App Store or iTunes Store - Apple Support

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

Avoid scams when you use Apple Cash --> Avoid scams when you use Apple Cash - Apple Support

Apple 'How to identify, avoid, and report phishing' video--> https://youtu.be/SR3Z3fXXjfw

Sounds like you received a scam email or pop-up.