This may not be something that you have considered before, but if you have ever bought a second-hand car, then it is worth checking that the tyres are the correct size for that make and model of vehicle.
When the car is first made, the manufactures recommend the correct tyres for a vehicle but you can chose to have different ones fitted, or sometimes they are fitted by the garage incorrectly.
Converting to a different size of tyre is possible, but there are still limits as to what tyres you can have and how to fit them correctly. If you get it wrong, the consequences can be dire. You also need to be aware that fitting tyres/ wheels of a different size on your vehicle, can invalidate your warranty.
If you want to change the wheel size of your car it is possible but it may mean that you need to also change other parts on your car to accommodate the new wheels and tyres. The size of the tyre is important because your car speedo, braking system, traction control and gear settings are all designed based on the standard wheel size. Anything different can have a negative impact on these aspects of the vehicle.