can anyone recommend me a best app for my iPhone?
It's hard for me to define the best, but this one does the job for me: Avira Free Mobile Security for iPhone - Find a lost phone
I use Avira since always without no issues, but I think the kind and amount of antivirus depends of how you browse Internet and where you plug your device.
I've been using the iPhone for 5 years. Not once have I heard of a non jailbroken iphone that got a virus. It just doesn't happen.
Actually, thats probbly the ony time u need it on iOS,, when the phone is jailbrocken
No, no no no no no no no. A thousand times, no.
Further reading: Why Apple iPhones Don't Need Antivirus Software