When pan frying, the amount of oil in the frying pan can range from absolutely no oil (especially when the foods to be fried contain fat or oil), to an amount of oil that comes slightly up the side of the food being fried.
Generally, quite a bit less than the bottom 1/3, up to 1/2, of the food will be in oil. The amount of oil is less that used in deep frying, where the food is at least half, to completely immersed, in oil.
Pan frying can be similar to sautéing, but in sautéing only the slightest amount of oil is always used and the ingredients are intended to be tossed or stirred while cooking.
One might distinguish pan frying from sautéing, stir frying, and deep frying in that, in pan frying, the food is not necessarily intended to be frequently stirred around, or turned repeated, but, rather, turned only once or twice during cooking.