Looking to find out how to power 2x 12v, 0.2amp, 3pin computer fans through an arduino uno
Although computer cooling fans draw low current, you can not feed them directly with Arduino. Typically, you need a buck or buck-boost converter that can be controlled by Arduino to change the input voltage of the cooling fans. But, you can simply use a ULN2803 L293, or L298 to control the fans by PWM. The speed of the fans is controlled by the duty cycle of the PWM. Don't forget to add a free-wheeling diode and maybe a capacitor to the output.

Good luck