If you want something you can request it or you can ask for it. Many people like “request” because it sounds more formal, more elegant; but to other people it just sounds pretentious. There are many instances in which plain old “ask” works better: “I’m asking my buddies to go camping with me.” “She asked him to walk the dog.” Except on wedding invitations, try to avoid “request” where “ask” will do as well.