Yes there’s lots of fraud on the Internet. That is irrelevant to this discussion. An app can only be installed of you open the App Store, tap on an app, then tap Get or Buy (as appropriate). And after you do that there is an “are you sure” dialog that requires your passcode or biometric confirmation. The app that you showed in your screen shot was updated today (or the day you took the screenshot). And the cloud symbol shows it isn’t on your phone.
You can also go to Settings, tap on your name, then Media & Purchases/View Account/Purchase History and browse for it to see the first time it was installed.
Is this a new phone that you purchased directly from Apple or an authorized reseller, or is it a used phone that was not reset to factory settings before you first used it?
When you open Settings and tap on your name are there any devices listed above “Sign out” that might have downloaded the app?