How do I know if my iPhone is hacked?

Those are common messages and are all scams. Apple will never send you a message that specifically says your phone is being hacked. Some of those messages even provide a phone number that claims it is for Apple Support, but you will only be calling a person that wants your Apple ID and Password to lock you out of your device. In other messages they may want you to download some fake software claiming to fix your issue, but will only give you more problems.

Your phone is not hacked unless you let someone use it for a an hour or so and also provided them with your Apple ID and Password.

Otherwise, the message that you see is not from Apple. It is a scam that is trying to trick you into buying useless software or tapping on a link that will ask for personal information.

Delete the message and any others that you might receive.

It's a scam. Ignore it. Your phone is not being hacked.

I had a pop up saying that I have 7 malware is the possible

A non-jailbroken phone cannot be hacked, get malware, or a virus. Ignore the scam message.

Drabsnake89 wrote:

I had a pop up saying that I have 7 malware is the possible

Not possible. The same thing applies to you from what the others have said on this thread.