Testing the resistance across several terminals on your ignition coil is the only safe and accurate way to tell if the coils is damaged or not. Measuring the primary and secondary resistance requires an ohmmeter, and a digital readout is best if you have access to one. Most ignition coils will fall into similar ranges when reading the resistance, but there can be some variation by manufacturer and coil type. If you are not sure what yours should be, check with the dealer service department.
Remove the negative battery cable from the battery with a wrench. Isolate the battery cable so that it can not contact the battery.
Locate the coil on your Ford engine. The coil looks like a black cylinder with a center wire similar to a spark plug wire and two side posts with nuts and wires attached.