Classification is Classification, for example , your brain knows all available colours, so each time I give you coloured T-Shirt, you will say (Green, Blue, Red). This is Classification called supervised learning because you have prior knowledge of available classes or categories (colours).
This is a basic question, but no problem you can ask whatever you want, I advise you to start with youtube you will find very good basic information.
You can see it as a supervised learning process, where you have predefined categories and an algorithm is trained to predict to which category new observations belong to.