Combustion is known to be the oxidation of an organic compound which means that the compound will turn into carbon dioxide and water molecules. Oxidation is almost the same but the main difference is the addition of oxygen with an element.
You will know if combustion is taking place because of the presence of heat and the item may also ignite and show light. When oxidation takes place, there will be no heat. It should be noted that combustion and oxidation are not the same processes. They have differences that will make it easier for you to determine what process has taken place.