Villi and microvilli are both found in the human body. The fact that the word 'villi' is present in the two words does not mean they are referring to the same thing. In fact, their functions in the body are different. Villi are like small projections from a mucous membrane, particularly those found in the intestines. Villi are very short in length; approximately, each villus is 1mn long. Inside villus, there exists microvillus.
Villi can also be called intestinal villi. The microvilli in them act only on the intestine lining by increasing the surface area so as to aid absorption. Microvilli, on the other hand, are generally found inside the various cells in the body; they are present inside the taste bud, and they are also functioning in the ear. The job of the microvilli is to increase the surface area of the cell, and as a result, they are aiding, absorption, adhesion, secretion, etc.