The MLS is the top soccer league in America. The EPL is the top soccer league in England.
The MLS does a very American thing by having playoffs to determine its champion. The EPL simply names the regular season champion as their champion.
In Europe, there are many special tournaments that are conducted throughout their regular seasons. Each country will pause their regular season play to have tournament play between leagues across Europe. Yes, these tournaments are based on the previous year's final regular season standings in each country.
We have tournaments between clubs and countries here from North and South America. It's a little different than what they do in Europe.