You need to create product variations when your product has different attributes. For example, if a product is available in more than one size and color, you need to create variations of the product for all available sizes and colors. Different variations can have different prices and different stock keeping units
PREREQUISITES: Before you create variations, you must have created the attributes according to which the product varies and the values of those attributes.
EXAMPLE: You sell a blouse that comes in sizes S and M and in colors blue and red. First, you create a product Blouse. Then, you create attribute Size and create values for this attribute – S and M. Then you create an attribute Color and create values for this attribute – Red and Blue. Finally, you must create the following four variations of the product Blouse: Size S, Size M, Color Red, and Color Blue.