This varies by camera mode & model.
In "manual" exposure mode changing any setting (ISO, Aperture, or Shutter speed) will change the exposure and you'll see this if you watch the digital "needle" in the viewfinder display. In other words dialing the exposure adjustments so the needle points at, say, "-1" is the same as dialing in "-1" stop of exposure compensation if the camera were any of the automatic modes.
In Av or Tv mode, the front dial sets your preferred setting (either aperture or shutter speed depending on which mode you selected) and the REAR dial adjusts exposure compensation. In "Program" mode the rear dial still controls exposure compensation, but the front dial controls "program shift".
The rear dial is only found on mid-level and above cameras (e.g. 1D series, 5D series, 6D, 7D series, and the mid-level bodies such as the 80D, 70D, 60D, etc.) It does not exist on entry level bodies ("Rebel" series in North America, "Kiss" series in Asia, and in the rest of the world these cameras have 3 or 4 numeric digits in the model number (e.g. 1300D, or 750D, etc.) The one exception is the 760D / T6s which does have a rear-dial. For any other model, you have to use the menu to adjust exposure compensation.