my phone keep saying i have viruis what app can i used

You DON'T have a virus. A non-jailbroken iPhone can't get one. You saw a scam message designed to make you believe you have one, so you will buy software/services you don't need for an issue you don't have.

Read this from Apple --> Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support

It is a scam. You will see these in the form of an advertisement when browsing less then legitimate websites. The purpose is to scare you into believing you have a virus and you need their software to fix it. These same kind of scams are seen in messages and emails as well. Don't fall for it.

Your phone is not saying that it has a virus. The scam messages that you are seeing are saying that your phone has a virus......when it does not.

The messages are trying to trick you to buy junk software that will not help your phone....but it will slow it down.

Delete the messages and keep working

Scammers also use similar messages to try to get you to call them for "help". The only "help" you will get is in them ripping you off, one way or another – and possibly selling your information to other criminals who want to rip you off in the future.

FTC – How To Spot, Avoid, and Report Tech Support Scams

"Tech support scammers may try to trick you with a pop-up window that appears on your computer screen. It might look like an error message from your operating system or antivirus software, and it might use logos from trusted companies or websites. The message in the window warns you about a security issue on your computer and tells you to call a phone number to get help.

If you get this kind of pop-up window on your computer, don’t call the number. Real security warnings and messages will never ask you to call a phone number."

None; a message warning of malware will only be legitimate if you manually started a scanner or uploaded a file to a website. If you did do that, delete the file involved or scan it on a computer.

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