Hi and welcome to APUG.
The C330 will work with any flash that triggers using a pc cord. There are pc synch terminals on each of the lenses, and you need to connect the pc cord to those terminals.
There is a cold "shoe" on the side of the camera, but that isn't really suitable for mounting a flash.
I don't know if Mamiya ever made an electronic flash for the C330. There are older flashbulb holders made by Mamiya, but unless you need flashbulbs for special purposes (cave exploration?) or value the retro "look", you probably don't want one of them.
If you have a Mamiya left hand trigger grip designed for the C330/RB-67, it has a cold shoe on the top that goes well with something like a Vivitar 283. I have one of those grips specially modified to take a Metz 60-CT series flash-head that worked well for on-camera flash when I was shooting weddings.
As I mentioned, each of the lenses has its own pc synch terminal. Each of those terminals has a M-X switch which is easy to accidentally change. Unless you are using M class flashbulbs, it is important to ensure that the switch is on X when you use an electronic flash. I've encountered a few Mamiya TLR lenses where someone has permanently glued the switch to the X position.
The leaf shutters in the lenses make flash work very satisfying, especially if you like to use fill flash.