Flour provides the structure for cake. The most commonly used types of flour in baking a cake are white and whole-wheat.
White flour is the ground inner kernel of the wheat berry; whole-wheat flour is ground hard wheat that is high in gluten. As white flour does not contain nearly the same amount fiber as whole-wheat flour, these are not interchangeable in recipes. However, you can usually substitute up to half the amount of wheat flour in a recipe that calls for white flour.
For those who are gluten intolerant, many alternatives for wheat flours exist. Chickpea, rice and tapioca flour are all common substitutes.
Use caution, however. You may need to adjust other ingredients if substituting any other flour than the one called for in the recipe.