There's no single universal location; some are easier to spot than others. You'll likely find it near the steering column, possibly near the lower left of the dashboard, or even sometimes under a small panel or cover.
Once you've located the release, pull or lift the lever/cable. You'll then need to go to the front of the car and lift the hood. There may be a hood prop or latch that needs to be engaged to hold the hood open once you've raised it.
