2003 ford expedition 4.6 v-8 will turn over but wont start

This is a wide open question, but the first thing to ask is if the vehicle had been in an accident or jolt of some kind, the fuel cutoff switch may need to be reset. That should be located in the rear of your vehicle on the drivers side in a panel just inside the rear hatch door. If that is not the issue, you will need to start eliminating items, like the fuel pump. That can be tested using a fuel pressure guage and connecting it to the schroeder valve on the fuel rail. If you are getting proper fuel, your next test can be checking the coil pack. I believe yours would be with each spark plug. There are many other items and details for each item to test, but you need to start eliminating the easiest possible problems first.