Boiling water is hardly a technique that needs explaining. It is one of the first and easiest cooking techniques we learn in the kitchen. The only potential problem caused by boiling is overcooking an ingredient.
Boiling is used for a wide range of ingredients, including grains and pasta (fresh pasta cooks more quickly than dried), starchy tubers and root vegetables like potatoes, yucca, yams, beets, rutabaga, parsnips, celery root and turnips, which can be boiled in salted water until tender.
Water boils at different temperatures, depending on your altitude. At sea level, water boils at 212 degrees F, while at higher elevations, where it meets less atmospheric pressure, it boils at a lower temperature.