You should find plenty of information on line regarding QlikView on mobile if you Google for it.
The original app that was available for iPhone has now been superseded. Generally apps are just available on a HTML5 web page rendered in the phone/tablets browser. When the QlikView app realises it is being accessed on a phone it offers to go into 'Small Device Mode' which is a way that small devices can more easily consume QlikView documents. The better approach though is to design documents specifically for the target device and change font size / page space used accordingly.
There is an app for iPad now which will allow a small amount of data to be cached for offline use. I don't know of anyone who is using this though.
The best way to see how QlikView behaves on a phone is to point your own phone to http://demo.qlik.com/ and look at the demos there.
To allow users to view your apps on their phone you either need to have a server exposed to the internet (with username and password protection) or the phone must be on your internal network via Wi-Fi or VPN.