Received a pop up saying my phone has 3 viruses. How do I fix this without compromising my personal information etc ?

Nothing to fix, it is phishing. iPhones do not get viruses unless jailbroken.

All messages coming with popups are fake. Ignore it and use Popup blocker an a good Adblocker like uBlock.

It isn’t legit. What app are you using when you see this message?

It's the same when you get a popup saying that you won US$10,000,000.