Update your display name or username in the mobile app
Select the "Menu" button in the bottom-right of the screen.
Select "Profile" in the menu to go to your profile.
Select "Edit Profile" on your profile page.
Modify your display name and username in the fields.
Once done, click "Save" at the top-right of the screen.
Update your display name or username in a browser
You can update your Display Name and Username in your user account:
Select your user icon in the top right corner to open the drop-down menu.
Select "Preferences" from the menu.
Select the "Account Details" section to expand it.
To modify your display name and username, click the pencil icon to the right of either one. Enter the new display name or username you would like to use.
Once done, scroll down and click "Save".
If your username is already in use by another member, you will receive a notice: "This username is already taken. Enter a unique username for yourself." You can modify your username again to something that is available.