The clutch master cylinder reservoir is located under the hood, on the left side firewall. The fluid in the reservoir will slowly decrease or drop as the clutch wears. As long as the fluid level is visible at or near the line on the reservoir body, it is not necessary to "top-off" the fluid level. However, add fluid if it is necessary.
Before removing the clutch master cylinder reservoir cap, make sure the vehicle is resting on level ground and clean all dirt away from the top of the reservoir.