Use the Edit Profile section of your account to edit your username, email, or password. To access this page, select the profile icon in the top right corner to pull out the right hand menu, then select "Account".
From the Account page click "Edit Profile" on the left to bring up your profile.
You can type in any field under "Basic Profile" to edit your login credentials, and select "Update" to confirm any changes. Keep in mind, you can only change your username once. If for any reason you need to change your username again contact email@example.com.
You may also include additional information for your public profile such as a profile image, a short biography, and more.