Chocolate is made from the fermented, roasted seeds of the tropical cacao tree. The seeds are used to make cocoa solids and cocoa butter.
Modern chocolate usually comes in dark, milk and white chocolate. All three of them have sugar added. Milk chocolate has milk added to it, and white chocolate doesn't have cocoa solids in it, only cocoa butter.
Chocolate is used to make a huge variety of sweets, desserts, cakes and drinks.