Depends on the vehicle. Give us more info.
If your engine has coil packs it will have one for each cyclinder. There are still a few engines that use just one coil but most use coil packs these days.
The 2000 Blazer with the 4.3 engine has one coil.
The 5.4L has 8 coil packs one on each spark plug. The 4.6L has only 2 coil block packs.
A 2001 Chrysler Town and Country has one coil pack.
One
I believe there are 8 coil packs...one sitting on top of each spark plug.
A 1997 Jeep Grand Cherokee has one ignition coil.
8 -one per cylinder
Eight, one for each cylinder.
Your truck does not have ignition coil. Instead, it has coil packs. The 5.4L has eight coil packs one on each spark plug. The 4.6L has two coil pack blocks 4 on each block.
If you are looking to purchase coil packs, you can find them at Canadian Tire. Another place would be Part Source. Any automotive place will carry coil packs.
Depending on the manufacturer, many coil packs mount on a large transistor plate that actually fires the coil pack. It's not uncommon for those transistor plate to fail.