What to do about virus on iphone

Ignore it. It's a scam.

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

https://support.apple.com/en-us/HT204759

About pop-up ads and windows in Safari

https://support.apple.com/en-us/HT203987

Delete spam calendars and events on iPhone

https://support.apple.com/en-us/HT211076

If running iOS 13 or earlier versions, check: Settings - Passwords & Accounts - Accounts - Any rogue entries here? If so, delete the rogue account. 

If running iOS 14, check: Settings - Calendar - Accounts - Any rogue entries here? If so, delete the rogue account. 

The Apple support article is below. 

Remove calendar spam

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