Zucchini comes in two types, green and yellow. Flavours are similar, yellow have a slightly firmer flesh. If flowers are still present these can be eaten. In Mediterranean countries the flowers are a highly sort after delicacy.
Zucchini keeps well for several days in the fridge and can be boiled, steamed or fried. But be careful not to overcook as they can easily become mushy and unappetising.