RC cars range widely in size, complexity, skill level, and cost. To find the appropriate RC model car for your kids, you need to consider age, experience, durability, and speed.
Many RC cars for younger kids have limited controls such as left wheels and right wheels, sort of like a skid-steer vehicle. While this sounds counter-intuitive, it becomes very natural to control each side independently. The conventional controller for an RC car has one stick for proportional forward and back, and another stick (or wheel) for proportional steering.
As controllers for these RC cars start out for beginners, it may begin with a single speed forward and reverse, and a left and right that isn’t proportional to the movement of the controller, so left and right is more like an on/off switch.