In addition to mechanical linkage, clutches can also be controlled by hydraulics. These systems use a master cylinder and slave cylinder to engage and disengage the clutch assembly.
The principal is the same as your brakes. When you apply your brake pedal, or in this case the clutch pedal, hydraulic pressure is forced out of the master cylinder into the slave cylinder, where it’s converted to mechanical motion. Hydraulic clutches are inherently self-adjusting, meaning they don't require periodic adjustment in the same way mechanical linkage does. So if you have a hydraulic clutch setup, it's not likely you'll ever have to adjust it. If you do decide to adjust it, be sure to consult your service manual for the proper procedure. For the most part, leave hydraulic clutches alone when it comes to adjustments. The only time you should need to do an adjustment is when you install a new master cylinder. Once that initial adjustment is made, that's pretty much all there is to it.