Virus on iPhone?

It means that virus and malware is software

with a computer one can install software from mails, websites, usb sticks.....

on un jail broken iOS devices one can only! Install any type of software from apples app store

so you cant get a virus unless you get it from apples App Store and if you do it will be a bit egg on the face of apple in terms of security of their store.

There are no known viruses that can affect iPhones that have not been jailbroken.

If you don't know what jailbreaking means, then chances are you have not done it at all, and you should have nothing to worry about.

No viruses on a standard iPhone, so nothing to protect from.

If your phone isn't jailbroken, then it does not have a virus or malware.

If you do not know what jailbroken is, then I would feel safe to say that your iPhone is not jailbroken. As KiltedTim states, you cannot get that unless you are jailbroken.