Every car on the road that runs on gasoline has spark plugs. Some cars even have 2 plugs per cylinder. Bust just like different cars have different motors, different motors have different spark plugs. On most cars, checking or changing your plugs is a simply DIY task. On a few cars, getting to the spark plugs requires a bit a disassembly or difficult access.
Most inline and V type engines have the plugs right on the top of the motor making access a snap.
H type and transversely mounted motors may have plugs mounted low and on the side of the motor or on the backside tight against the firewall. These plugs may be difficult to access or require the removal of the intake manifold. These types of motors are better left to the professional.