You can change your display name and username in the 'My profile' section of the app. To change these details:
Tap on your username or photo in the top left of your Home Screen to open the 'My profile' page.
Tap the pencil icon at the top right of the screen to edit your profile.
Tap on and then edit your 'Display name' or 'Username' to make changes.
The ‘update’ button will appear in the top right corner of the screen. When you are finished tap 'update' to confirm your changes.
Your username begins with '@' and is unique. Try and pick something original to avoid usernames that have already been taken.