Sometimes Desiccated Coconut is referred to as Coconut Powder by some manufacturers to mean dried, shredded coconut.
Most often, though, Coconut Powder is meant to be a very fine powder, like a flour. It is made by evaporating coconut milk. To use, reconstitute in water. This is good to have on hand if you cook Asian just often enough that you are going to get caught without Coconut Milk.
The instant powder is designed to mix more easily than the regular.
Cooking Tips
To make Coconut Milk from Coconut Powder: 1 packet of instant Coconut Powder with 13 oz (400 ml) of lukewarm water or 1 ½ oz (50g) of regular Coconut Powder with 8 ½ oz (250 ml) of hot water.
To make Coconut Cream from Coconut Powder: 1 packet of instant Coconut Powder with 6 ½ oz (200 ml ) of lukewarm water or 2 ½ oz (80g) of regular Coconut Powder with 6 ½ oz (200 ml ) of hot water.