The very first level of certification for drone operations is called “basic”, and that is for someone who wants to get a drone to play with more for fun, etc. There's a minimum age limit of 14 for that, I believe, but you're very limited as to where you can actually operate them.
The one area that must be negotiated if you are conducting a drone operation is if the area is considered restricted, maybe due to a police operation, or if it's controlled airspace, where you could impact air operations. In order to function in those zones, you must have at least an advanced limit certification. An advanced limit certification allows you to function in controlled airspace. If the aircraft meets the criteria, it can be over people. Transport Canada has very strict guidelines on how these are to be operated. They're also limited to what's called “visual line of sight”, or VLOS.
With the increasing requirement to operate at an extended range with drones, they have recently introduced what's called the level 1 complex rating. That permits you, under given conditions, if they're all approved by Transport Canada, to run at what's known as “beyond visual line of sight”. That's where you are remotely operating a drone beyond your line of sight at a point that it's so far away you can't see it and you're relying entirely on the operating system, the machine's camera and its GPS data to let you know exactly where it is and what it is doing.
Those last two—advanced and level 1—are the ones that are required if you wish to operate as a commercial operator.