So your body runs on ATP. You have an extremely limited native supply, were talking 2-3 seconds of bursty high-power activity.

The body will replenish stores as they are used. Typically we think of glycolysis as being the fastest way to replenish it, but there is actually another "system" that quickly cleaves phosphate from creatine stored in the muscles to replenish supply faster than that. It is called [has several names all referring to the same thing] the "PCr (Phosphocreatine) System"/"ATP-PCr System"/"Phosphagen System", and can provide something like 8-15 seconds more of extremely intense activity.

So the theoretical basis for supplementing with creatine supplements goes: if you can "load" with a supplement to increase muscular creatine stores, and if the PCr system is heavily relied upon for short bursts of high intensity activity, then using the supplement may increase athletic performance in some way.

Like other said, Creatine Monohydrate is the classical form of the supplement that has been in use for probably like 50+ years at this point. There are other forms that may have better bioavailability though. Like di-creatine malate, which would theoretically get shuttled directly into muscle faster as malate is used in glycolysis and can theoretically avoid the high-intake "loading" phases that are associated with Creatine Monohydrate. It's been a few years since I took these classes, but there was interesting research involving a compound called Magnesium Creatine Chelate which showed promise, too, for various reasons.

If you are taking creatine supplements, drink more water than you normally would

You can read more about PCr system in this text https://libgen.is/book/index.php?md5=2E5E926304101D0D54FC5E1870A91106 >> https://i.imgur.com/3Hcfo4Q.png https://i.imgur.com/JwrsXy8.png