Changing your name is easy! Visit your Twitter Account settings to change either your real name and/or username.
NOTE: Changing your username will not affect your existing followers, Direct Messages, or @replies. Your followers will simply see a new username next to your profile photo when you update. We suggest you send out an update to your followers before you change your username, because any @replies or Direct Messages sent to your old username will not be associated with your account once you've switched to your new username.
If you're having trouble with usernames, please see our username troubleshooting article for more information.