I am 99% sure that THE Torque Pro app that everyone raves about is not available on apple devices, only android. There are a few knockoffs on the Apple app store that have logos and names that look like the real thing.
If you want a good OBD app for iPhone, look at OBDFusion or the OBDLink app, which is the same thing as OBDFusion but requires an OBDLink bluetooth adapter. Honestly, these apps are more powerful than Torque Pro in my experience, but their interfaces are not quite as nice.
With Ford vehicles, the Forscan Lite app is also exceptionally awesome. There is also the Forscan software available for your PC as well which is capable of reading and writing to various modules in your vehicle.