Yes for plowing streets.
The MTO must license you to plow regular streets. If an MTO agent or a cop sees you plowing without a license you will be ****ed.
I’m not sure what the regulations are for plowing driveways etc are though.
Usually large snow plowing trucks (built only to snow plow and salt) are licensed by the MTO in large towns/regions for the streets. So if the average joe that’s driving his jeep down the street decides to put his plow down on a snowy day to make way, he can get in big trouble.
With what’s happened to the woman that was taken out by a plow on Sunday, I’m pretty sure things will get a little bit tighter with that too. From what I understand there’s talks about putting a proper training course in place for the drivers of any plow, private or commercial, otherwise it will be illegal to do it.