There are two ways to use MCCC whilst in the game: by clicking on a Sim, or, household computer. You can use it to change the clock in your game or to make your Sim pregnant. The mod has many different functions and features.
Once installed, it can be found easily in-game. The MC Command Center (MCCC/MCMM) is a large Sims 4 mod or rather a group of mods. Not all interactions are available, though.
These commands take the form of interactions performed between two Sims. The MC Control module allows control of NPC Sims, letting you give them limited commands as if they were an active Sim.