Padel is a racquet sport. It is different from the sport known in the US and Canada as paddle tennis. Padel is typically played in doubles on an enclosed court roughly 25% smaller than the size of a tennis court. Scoring is the same as normal tennis and the balls used are similar but with a little less pressure.
paddle tennis and platform tennis are three similar but different sports. To make things even more confusing, platform tennis is often called "paddle tennis" by its players and sometimes only "paddle". Needless to say, it can be hard to know exactly which sport a person is talking about.
Originally developed on land unsuitable or too small for traditional tennis courts, the space under the platform allows for the installation of heating equipment that facilitates year-round play (as it melts any snow). As a result, platform tennis is especially popular in winter when tennis courts may be out of action.