What is the total max supply?

Could you please elaborate on the concept of 'total max supply' in the context of cryptocurrencies? Specifically, I'm interested in understanding how this figure is determined, what implications it has on the value and stability of a particular coin, and whether there are any exceptions to this limit? I've noticed that some cryptocurrencies advertise having a limited supply, while others seem to have an unlimited or adjustable supply. Could you explain the differences and their potential impact on investors?