I have a 2005 Ford Taurus SE 3.0L. How many spark plugs do I need to buy to replace them all for this particular vehicle? Iv'e learned that each vehicle is different in numbers of spark plugs they consist of. How many spark plugs does a 2005 Ford Taurus SE 3.0L have?

Is it a V 4, V 6 or V 8?

You need to buy 6 spark plugs. Go with the exact Motorcraft plugs that are in the car. This link may help you to be able to change the rear plugs yourself:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-8.html#post1375876

Change platinum plugs at least every 50,000 miles, for best performance and gas mileage.

Does auto light AP104 spark plugs fit in a 2005 Ford Taurus

Yes, those will work.