How to power new case fans

[Onixom]

So I'm going to be buying a new case for my computer and have made sure that it is compatible. However my question is that with the new case there are fans that are installed already, how are they powered? do i need to plug them in the motherboard or power supply, or are they powered by the case when it's plugged in?

 

[CountMike]

Well, all I can say is "it depends" could be any of those ways and few other ones, like separate aftermarket fan controller etc.