A Tournament on a Four-Year Cycle
Since its first edition in 1930, the FIFA World Cup has been held once every four years. That four-year gap is built into the competition. Each tournament is the climax of a long, separate qualifying process that itself takes years to play through. So the cycle is not just about the final tournament — it is about the entire journey leading up to it.
The Years It Did Not Happen
There is one big gap in the otherwise unbroken run. After the 1938 tournament, no World Cup was held in 1942 or 1946. The Second World War made the competition impossible to organise during those years, and FIFA did not resume it until 1950. Since then, the four-year cadence has held steady through every subsequent tournament.
The Same Beat as the Olympics
The four-year cycle of the World Cup is shared with several other major sporting events, most famously the Summer Olympic Games. Both competitions are big enough that they need years between editions for cities, countries, and players to prepare. The result is that football fans grow used to thinking about the World Cup in four-year terms — counting up to the next one almost as soon as the last one has finished.
Source
This article was written using information from Wikipedia.