There are several standards for plugs. Types C, E, F, and G. Only the slim ungrounded plugs will fit in type C, E, and F sockets. Grounded type F plugs will be ungrounded in C or E sockets, and grounded type E plugs don’t fit in anything but a type E sockets. If the type C or E are the full round plug, neither will fit in a type F socket even if it is ungrounded (I know this because I had to trim excess plastic from a type C plug to use it in a type F socket. Type G is used by Ireland Malta and Cyprus and is entirely incomparable with the other types. Type G also makes an excellent caltrop and will fuck up your foot in a profound way if you step on it. Then the Italians swiss and Danes all have their own style of plug. Most of the countries have a mixture of type C and whatever earthed version that country prefers.
The above picture is a typical situation in Norway. The left most type C plug only fits in the type F socket because I butchered it. And the earthed type F plug is only earthed in a type F socket. Many older buildings only have type C sockets in most rooms (the kitchen and bathroom are always upgraded to type F and there’s usually a cluster of type F sockets in the living room on the same wall as the TV).
As for the voltage requirements that’s only a thing because the entirety of Europe is connected in one large grid. Obviously Canada wouldn’t be.
You get adapters for that. Also Japan uses both systems in the same country. Everything from Osaka to the west is 60Hz and everything from Tokyo to the east is 50hz. They cope (they both use 100V).