Received a virus notice

All such messages are scams presented by criminals. Close the offending page and avoid sites that are involved in such bogus advertising tactics. Do not interact with the message or the sender. Never, never, never download anything based on a popup message.

Phony "tech support" / "ransomware" popup… - Apple Community

That message is spam! Apple would never send such a message. Do not reply to message, just delete and move on...

Nothing was infected because what you had received was a fake message.

This is a scam!!

If you receive a suspicious email or SMS text message that looks like it's supposed to be from Apple, please email it to reportphishing@apple.com. 

▷ Recognize and avoid phishing messages, phony support calls, and other scams.