Provided your teeth are healthy and strong, there is no reason why you shouldn’t benefit from orthodontics as an adult. Many adults didn’t get the chance to have treatment as children, or perhaps will have worn braces as a child but have since had an orthodontic relapse, which is where the teeth begin to drift back towards their original positions. This could be a natural part of ageing or due to failure to wear a retainer as recommended.
Adult orthodontics can correct teeth that are significantly out of alignment so they look more attractive and are easier to keep clean. Some people may have teeth that are only slightly out of position, in which case cosmetic braces may provide the best solution.