How do you remove virus

Where are you seeing this? If an alert by mail, it is a SCAM. iPhones do not get viruses, unless they have been jailbroken. See this link...

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

What is showing this? If it is some sort of popup or email, or calendar entry it is spam, you do not have a virus.

It's a scam.

Delete it and move on.