One of them is the humans, called Terrans. It is a relatively easy-to-maintain race, with a balanced cost of individual buildings and units, requiring the erection of buildings with the participation of a worker (SCV).
The Protoss are a highly technologically advanced alien race that is quite expensive to maintain, but allows the simultaneous summoning of buildings with the participation of only one worker (Probe), who does not participate in the entire process of building, but only initiates their materialization.
The last race is the Zerg, which is a rather expansive alien race, focused on numerical superiority. The cost of creating units and buildings compared to the other races is lower. The creation of buildings involves the sacrifice of a worker (Drone), which evolves into the target stage.
In each case, the player can choose to create units that fight at close quarters or at a distance, as well as infantry and aviation. Each race has its own unique characteristics, which require adjusting strategies to achieve the best results.