The illuminated Check Engine light (CEL) means that the car’s OBD2 system has stored a trouble code (or two, or three…). Go to Auto Zone, Advance Auto Parts, O’Reilly, or another parts retailer that will read the stored trouble codes free-of-charge, then come back to this thread to report those codes.
Incidentally, the Check Engine Light has absolutely nothing to do with the level of oil in your engine, so please don’t rely on that light to tell you when you need to add oil. Similarly, do not rely on the Oil Pressure Warning Light to inform you of a low oil level. You should check the dipstick frequently, especially if your car consumes some oil between oil changes.