Mitosis will take place any where in the body except in locations where meiosis is occurring. Meiosis is the process by which sex cells are created. In other words, meiosis produces gametes that each have half of a person's genetic information.
Mitosis doesn't produce haploid gametes. Mitosis produces diploid copies of existing cells. You can think of mitosis as cellular cloning. When your body needs more of a certain type of cell, the cell goes through mitosis. For example, when you lift weights, you actually tear the muscle fibers. Your body needs to generate more muscle cells in order to fill in those tears.
So muscle cells go through mitosis, produce copies of muscle cells, and the muscle tears are filled in. Your skin is constantly going through mitosis as it generates layer after layer of fresh skin cells. Your hair does the same thing. Your digestive system is a high friction environment, so its existing cells are constantly being rubbed away. The cells are constantly going through mitosis in order to replace the lost cells.