How did oil lamps work?

Oil lamps are containers filled with oils. These lamps work using capillary action by which the wick helps to burn the fuel using a slow yet effective action. To get the best results, the oil is made too steep, and as a result, the oil lamp burns and gives off heat and light.
The presence of narrow pores in the wick helps the capillary action until the fuel dries out. This slow-motion helps to make the oil rise in the wick and burn.