How do i know if i have virus protection built in my Iphone 13?

it's not from apple or google

the only way to install software on nonjailbroken ios devices is apple app store, no site, or link or SMS or mail or anything can install any type of software on your device

read

Getting pop ups from website on iPhone; i… - Apple Community

Block pop-ups in Safari on iPhone - Apple Support

more

iphone block scan popups - Google-

Viruses are a type of malware that work by spreading copies of themselves from an infected piece of code to other infected pieces of code. iOS is very sandboxed. Even if an infected app somehow made it into the App Store and you installed it, it wouldn't be able to infect other apps. A "virus" that can't spread isn't much of a virus. An "anti-virus" app that can't scan your apps for (non-existent) viruses also isn't much of an anti-virus app, either.

But fear of viruses is something that dishonest marketers, and outright criminals, like to use to panic their victims into purchasing worthless "security" apps (to solve non-existent "problems"). Or into calling phone numbers that belong to scammer call centers where criminals posing as "tech support" are waiting to rip off anyone who calls.

The message is a scam that is trying to trick you into buying junk software that you do not need to fix a problem that you do not have.

Close the message and keep working. Ignore any other messages like this that you might see.