can I change only the spark plug on my vehicle or do I have to change out coil a

Coil on plug ignition system .. Not equipped with "plug wires" .. Video link below should help: https://youtu.be/Hawluu9K19s

If you are changing the spark plugs because it is by time or mileage, I would change the spark plug wires. You do not need to change the coil. However, if you have a misfire in a certain cylinder, then you may need to change the coil.